Search tips
Search criteria

Results 1-23 (23)

Clipboard (0)

Select a Filter Below

more »
Year of Publication
Document Types
author:("Liu, sii")
1.  Genetic diversity and population structure of Rheum tanguticum (Dahuang) in China 
Chinese Medicine  2014;9(1):26.
Wild Rheum tanguticum (Dahuang in Chinese) has becoming endangered in China. This study aims to examine the genetic structure and genetic diversity of R. tanguticum within species, and the genetic differentiation within and among populations in China.
The variability and structure of 19 populations of R. tanguticum were investigated by their chloroplast DNA matK sequences. The genetic diversity index was calculated by Dnasp, PERMUT, and Arlequin 3.0 software, and a neighbor-joining (NJ)-tree was constructed by MEGA 5.0 software.
Fifteen haplotypes were obtained based on the matK sequence analysis. The mean genetic diversity within species was 0.894, and the genetic variability among populations (67.6%) was relatively higher than that within populations (13.88%) according to the AMOVA and PERMUT analyses. The NJ-tree and a pairwise difference analysis indicated geographical isolation of R. tanguticum. The gene flow among populations was 0.05, indicating a genetic drift among some populations, which was also confirmed by the NJ-tree and haplotype distributions. Furthermore, a mismatch distribution analysis revealed the molecular evolution of R. tanguticum.
Genetic diversity among and within populations of R. tanguticum in China was demonstrated.
PMCID: PMC4223855  PMID: 25383092
2.  Just like the rest of evolution in Mother Nature, the evolution of cancers may be driven by natural selection, and not by haphazard mutations 
Oncoscience  2014;1(9):580-590.
Sporadic carcinogenesis starts from immortalization of a differentiated somatic cell or an organ-specific stem cell. The immortalized cell incepts a new or quasinew organism that lives like a parasite in the patient and usually proceeds to progressive simplification, constantly engendering intermediate organisms that are simpler than normal cells. Like organismal evolution in Mother Nature, this cellular simplification is a process of Darwinian selection of those mutations with growth- or survival-advantages, from numerous ones that occur randomly and stochastically. Therefore, functional gain of growth- or survival-sustaining oncogenes and functional loss of differentiation-sustaining tumor suppressor genes, which are hallmarks of cancer cells and contribute to phenotypes of greater malignancy, are not drivers of carcinogenesis but are results from natural selection of advantageous mutations. Besides this mutation-load dependent survival mechanism that is evolutionarily low and of an asexual nature, cancer cells may also use cell fusion for survival, which is an evolutionarily-higher mechanism and is of a sexual nature. Assigning oncogenes or tumor suppressor genes or their mutants as drivers to induce cancer in animals may somewhat coerce them to create man-made oncogenic pathways that may not really be a course of sporadic cancer formations in the human.
PMCID: PMC4278337  PMID: 25594068
evolution; cancer; oncogenes; tumor suppressor genes; mutation
3.  Necrosis, and then stress induced necrosis-like cell death, but not apoptosis, should be the preferred cell death mode for chemotherapy: clearance of a few misconceptions 
Oncoscience  2014;1(6):407-422.
Cell death overarches carcinogenesis and is a center of cancer researches, especially therapy studies. There have been many nomenclatures on cell death, but only three cell death modes are genuine, i.e. apoptosis, necrosis and stress-induced cell death (SICD). Like apoptosis, SICD is programmed. Like necrosis, SICD is a pathological event and may trigger regeneration and scar formation. Therefore, SICD has subtypes of stress-induced apoptosis-like cell death (SIaLCD) and stress-induced necrosis-like cell death (SInLCD). Whereas apoptosis removes redundant but healthy cells, SICD removes useful but ill or damaged cells. Many studies on cell death involve cancer tissues that resemble parasites in the host patients, which is a complicated system as it involves immune clearance of the alien cancer cells by the host. Cancer resembles an evolutionarily lower-level organism having a weaker apoptosis potential and poorer DNA repair mechanisms. Hence, targeting apoptosis for cancer therapy, i.e. killing via SIaLCD, will be less efficacious and more toxic. On the other hand, necrosis of cancer cells releases cellular debris and components to stimulate immune function, thus counteracting therapy-caused immune suppression and making necrosis better than SIaLCD for chemo drug development.
PMCID: PMC4284620  PMID: 25594039
Apoptosis; Cancer therapy; Carcinogenesis; Evolution; Hyperthermia
4.  Whole genome sequencing of Ethiopian highlanders reveals conserved hypoxia tolerance genes 
Genome Biology  2014;15(2):R36.
Although it has long been proposed that genetic factors contribute to adaptation to high altitude, such factors remain largely unverified. Recent advances in high-throughput sequencing have made it feasible to analyze genome-wide patterns of genetic variation in human populations. Since traditionally such studies surveyed only a small fraction of the genome, interpretation of the results was limited.
We report here the results of the first whole genome resequencing-based analysis identifying genes that likely modulate high altitude adaptation in native Ethiopians residing at 3,500 m above sea level on Bale Plateau or Chennek field in Ethiopia. Using cross-population tests of selection, we identify regions with a significant loss of diversity, indicative of a selective sweep. We focus on a 208 kbp gene-rich region on chromosome 19, which is significant in both of the Ethiopian subpopulations sampled. This region contains eight protein-coding genes and spans 135 SNPs. To elucidate its potential role in hypoxia tolerance, we experimentally tested whether individual genes from the region affect hypoxia tolerance in Drosophila. Three genes significantly impact survival rates in low oxygen: cic, an ortholog of human CIC, Hsl, an ortholog of human LIPE, and Paf-AHα, an ortholog of human PAFAH1B3.
Our study reveals evolutionarily conserved genes that modulate hypoxia tolerance. In addition, we show that many of our results would likely be unattainable using data from exome sequencing or microarray studies. This highlights the importance of whole genome sequencing for investigating adaptation by natural selection.
PMCID: PMC4054780  PMID: 24555826
5.  NitroDIGE analysis reveals inhibition of protein S-nitrosylation by epigallocatechin gallates in lipopolysaccharide-stimulated microglial cells 
Nitric oxide (NO) is a signaling molecule regulating numerous cellular functions in development and disease. In the brain, neuronal injury or neuroinflammation can lead to microglial activation, which induces NO production. NO can react with critical cysteine thiols of target proteins forming S-nitroso-proteins. This modification, known as S-nitrosylation, is an evolutionarily conserved redox-based post-translational modification (PTM) of specific proteins analogous to phosphorylation. In this study, we describe a protocol for analyzing S-nitrosylation of proteins using a gel-based proteomic approach and use it to investigate the modes of action of a botanical compound found in green tea, epigallocatechin-3-gallate (EGCG), on protein S-nitrosylation after microglial activation.
To globally and quantitatively analyze NO-induced protein S-nitrosylation, the sensitive gel-based proteomic method, termed NitroDIGE, was developed by combining two-dimensional differential in-gel electrophoresis (2-D DIGE) with the modified biotin switch technique (BST) using fluorescence-tagged CyDye™ thiol reactive agents to label S-nitrosothiols. The NitroDIGE method showed high specificity and sensitivity in detecting S-nitrosylated proteins (SNO-proteins). Using this approach, we identified a subset of SNO-proteins ex vivo by exposing immortalized murine BV-2 microglial cells to a physiological NO donor, or in vivo by exposing BV-2 cells to endotoxin lipopolysaccharides (LPS) to induce a proinflammatory response. Moreover, EGCG was shown to attenuate S-nitrosylation of proteins after LPS-induced activation of microglial cells primarily by modulation of the nuclear factor erythroid 2-related factor 2 (Nrf2)-mediated oxidative stress response.
These results demonstrate that NitroDIGE is an effective proteomic strategy for “top-down” quantitative analysis of protein S-nitrosylation in multi-group samples in response to nitrosative stress due to excessive generation of NO in cells. Using this approach, we have revealed the ability of EGCG to down-regulate protein S-nitrosylation in LPS-stimulated BV-2 microglial cells, consistent with its known antioxidant effects.
PMCID: PMC3922161  PMID: 24472655
Epigallocatechin-3-gallate; Lipopolysaccharides; Microglia; Neuroinflammation; Nitric oxide; S-Nitrosylation
6.  RiceWiki: a wiki-based database for community curation of rice genes 
Nucleic Acids Research  2013;42(Database issue):D1222-D1228.
Rice is the most important staple food for a large part of the world’s human population and also a key model organism for biological studies of crops as well as other related plants. Here we present RiceWiki (, a wiki-based, publicly editable and open-content platform for community curation of rice genes. Most existing related biological databases are based on expert curation; with the exponentially exploding volume of rice knowledge and other relevant data, however, expert curation becomes increasingly laborious and time-consuming to keep knowledge up-to-date, accurate and comprehensive, struggling with the flood of data and requiring a large number of people getting involved in rice knowledge curation. Unlike extant relevant databases, RiceWiki features harnessing collective intelligence in community curation of rice genes, quantifying users' contributions in each curated gene and providing explicit authorship for each contributor in any given gene, with the aim to exploit the full potential of the scientific community for rice knowledge curation. Based on community curation, RiceWiki bears the potential to make it possible to build a rice encyclopedia by and for the scientific community that harnesses community intelligence for collaborative knowledge curation, covers all aspects of biological knowledge and keeps evolving with novel knowledge.
PMCID: PMC3964990  PMID: 24136999
7.  Stress Responsive Proteins Are Actively Regulated during Rice (Oryza sativa) Embryogenesis as Indicated by Quantitative Proteomics Analysis 
PLoS ONE  2013;8(9):e74229.
Embryogenesis is the initial step in a plant’s life, and the molecular changes that occur during embryonic development are largely unknown. To explore the relevant molecular events, we used the isobaric tags for relative and absolute quantification (iTRAQ) coupled with the shotgun proteomics technique (iTRAQ/Shotgun) to study the proteomic changes of rice embryos during embryogenesis. For the first time, a total of 2 165 unique proteins were identified in rice embryos, and the abundances of 867 proteins were actively changed based on the statistical evaluation of the quantitative MS/MS signals. The quantitative data were then confirmed using multiple reactions monitoring (MRM) and were also supported by our previous study based on two-dimensional gel electrophoresis (2 DE). Using the proteome at 6 days after pollination (DAP) as a reference, cluster analysis of these differential proteins throughout rice embryogenesis revealed that 25% were up-regulated and 75% were down-regulated. Gene Ontology (GO) analysis implicated that most of the up-regulated proteins were functionally categorized as stress responsive, mainly including heat shock-, lipid transfer-, and reactive oxygen species-related proteins. The stress-responsive proteins were thus postulated to play an important role during seed maturation.
PMCID: PMC3776822  PMID: 24058531
8.  Quantitative Evaluation of the Mitochondrial Proteomes of Drosophila melanogaster Adapted to Extreme Oxygen Conditions 
PLoS ONE  2013;8(9):e74011.
Mitochondria are the primary organelles that consume oxygen and provide energy for cellular activities. To investigate the mitochondrial mechanisms underlying adaptation to extreme oxygen conditions, we generated Drosophila strains that could survive in low- or high-oxygen environments (LOF or HOF, respectively), examined their mitochondria at the ultrastructural level via transmission electron microscopy, studied the activity of their respiratory chain complexes, and quantitatively analyzed the protein abundance responses of the mitochondrial proteomes using Isobaric tag for relative and absolute quantitation (iTRAQ). A total of 718 proteins were identified with high confidence, and 55 and 75 mitochondrial proteins displayed significant differences in abundance in LOF and HOF, respectively, compared with the control flies. Importantly, these differentially expressed mitochondrial proteins are primarily involved in respiration, calcium regulation, the oxidative response, and mitochondrial protein translation. A correlation analysis of the changes in the levels of the mRNAs corresponding to differentially regulated mitochondrial proteins revealed two sets of proteins with different modes of regulation (transcriptional vs. post-transcriptional) in both LOF and HOF. We believe that these findings will not only enhance our understanding of the mechanisms underlying adaptation to extreme oxygen conditions in Drosophila but also provide a clue in studying human disease induced by altered oxygen tension in tissues and cells.
PMCID: PMC3771901  PMID: 24069262
9.  Thermal Stability of Glucokinases in Thermoanaerobacter tengcongensis 
BioMed Research International  2013;2013:646539.
In the genome of Thermoanaerobacter tengcongensis, three genes belonging to ROK (Repressor, ORF, and Kinase) family are annotated as glucokinases (GLKs). Using enzyme assays, the three GLKs were identified as ATP-dependent GLK (ATP-GLK), ADP-dependent GLK (ADP-GLK), and N-acetyl-glucosamine/mannosamine kinase (glu/man-NacK). The kinetic properties of the three GLKs such as Km, Vmax, optimal pH, and temperature were characterized, demonstrating that these enzymes performed the specific functions against varied substrates and under different temperatures. The abundance of ATP-GLK was attenuated when culture temperature was elevated and was almost undetectable at 80°C, whereas the ADP-GLK abundance was insensitive to temperature changes. Using degradation assays, ATP-GLK was found to have significantly faster degradation than ADP-GLK at 80°C. Co-immunoprecipitation results revealed that heat shock protein 60 (HSP60) could interact with ATP-GLK and ADP-GLK at 60 and 75°C, whereas at 80°C, the interaction was only effectively with ADP-GLK but not ATP-GLK. The functions of GLKs in T. tengcongensis are temperature dependent, likely regulated through interactions with HSP60.
PMCID: PMC3766608  PMID: 24058911
10.  MAVS recruits multiple ubiquitin E3 ligases to activate antiviral signaling cascades 
eLife  2013;2:e00785.
RNA virus infections are detected by the RIG-I family of receptors, which induce type-I interferons through the mitochondrial protein MAVS. MAVS forms large prion-like polymers that activate the cytosolic kinases IKK and TBK1, which in turn activate NF-κB and IRF3, respectively, to induce interferons. Here we show that MAVS polymers recruit several TRAF proteins, including TRAF2, TRAF5, and TRAF6, through distinct TRAF-binding motifs. Mutations of these motifs that disrupted MAVS binding to TRAFs abrogated its ability to activate IRF3. IRF3 activation was also abolished in cells lacking TRAF2, 5, and 6. These TRAF proteins promoted ubiquitination reactions that recruited NEMO to the MAVS signaling complex, leading to the activation of IKK and TBK1. These results delineate the mechanism of MAVS signaling and reveal that TRAF2, 5, and 6, which are normally associated with NF-κB activation, also play a crucial role in IRF3 activation in antiviral immune responses.
eLife digest
The innate immune system can detect and destroy viruses, bacteria and other pathogens that enter the human body. In particular, inside cells, viral RNA can bind to and activate a protein called RIG-I. This protein switches on another protein, called MAVS, which can activate other copies of itself. These MAVS molecules then aggregate together on the membrane of mitochondria and send a signal that leads to the production of small proteins, called cytokines, which stimulate an inflammatory response and ultimately neutralize the virus.
Although many of the proteins that are activated by MAVS in the innate immunity signaling pathway have been identified, precisely how MAVS transmits this signal is unknown. Now, Liu et al. explore how this protein can propagate signals in the innate immune response by monitoring activation of the transcription factors IRF3 and NF-κB, which transcribe cytokine genes.
Previous studies have suggested that a protein known as ubiquitin is needed to activate RIG-I, and that this protein collaborates with MAVS to signal through the innate immunity pathway. Liu et al. found that a group of proteins including TRAF2, TRAF5, TRAF6 and LUBAC relay the antiviral signal by binding to MAVS. These so-called ‘E3 ligases’ string ubiquitin together in chains called polyubiquitin, which is essential for activating signaling after, or downstream of, MAVS; however, the association of these E3 ligases with MAVS also requires that multiple copies of MAVS cluster together.
MAVS, the TRAF proteins and LUBAC collectively recruit other innate immunity pathway proteins to activate IRF3 and NF-κB, and thus transcription of the genes that control the innate immunity response. Together, these results show the intricate interplay of proteins needed to eliminate viruses from the body.
PMCID: PMC3743401  PMID: 23951545
MAVS; innate immunity; virus; ubiquitin; signaling; mitochondria; Human; Mouse; Viruses
11.  Proteolytic Characteristics of Cathepsin D Related to the Recognition and Cleavage of Its Target Proteins 
PLoS ONE  2013;8(6):e65733.
Cathepsin D (CD) plays an important role in both biological and pathological processes, although the cleavage characteristics and substrate selection of CD have yet to be fully explored. We employed liquid chromatography-tandem mass spectrometry (LC-MS/MS) to identify the CD cleavage sites in bovine serum albumin (BSA). We found that the hydrophobic residues at P1 were not only a preferential factor for CD cleavage but that the hydrophobicity at P1’ also contributed to CD recognition. The concept of hydrophobic scores of neighbors (HSN) was proposed to describe the hydrophobic microenvironment of CD recognition sites. The survey of CD cleavage characteristics in several proteins suggested that the HSN was a sensitive indicator for judging the favorable sites in peptides for CD cleavage, with HSN values of 0.5–1.0 representing a likely threshold. Ovalbumin (OVA), a protein resistant to CD cleavage in its native state, was easily cleaved by CD after denaturation, and the features of the cleaved peptides were quite similar to those found in BSA, where a higher HSN value indicated greater cleavability. We further conducted two-dimensional gel electrophoresis (2DE) to find more proteins that were insensitive to CD cleavage in CD-knockdown cells. Based on an analysis of secondary and three-dimensional structures, we postulated that intact proteins with a structure consisting of all α-helices would be relatively accessible to CD cleavage.
PMCID: PMC3688724  PMID: 23840360
12.  SnapShot: Pathways of Antiviral Innate Immunity 
Cell  2010;140(3):436-436.e2.
PMCID: PMC3586550  PMID: 20144765
13.  The Temperature Dependent Proteomic Analysis of Thermotoga maritima 
PLoS ONE  2012;7(10):e46463.
Thermotoga maritima (T. maritima) is a typical thermophile, and its proteome response to environmental temperature changes has yet to be explored. This study aims to uncover the temperature-dependent proteins of T. maritima using comparative proteomic approach. T. maritima was cultured under four temperatures, 60°C, 70°C, 80°C and 90°C, and the bacterial proteins were extracted and electrophoresed in two-dimensional mode. After analysis of gel images, a total of 224 spots, either cytoplasm or membrane, were defined as temperature-dependent. Of these spots, 75 unique bacterial proteins were identified using MALDI TOF/TOF MS. As is well known, the chaperone proteins such as heat shock protein 60 and elongation factor Tu, were up-regulated in abundance due to increased temperature. However, several temperature-dependent proteins of T. maritima responded very differently when compared to responses of the thermophile T. tengcongensis. Intriguingly, a number of proteins involved in central carbohydrate metabolism were significantly up-regulated at higher temperature. Their corresponding mRNA levels were elevated accordingly. The increase in abundance of several key enzymes indicates that a number of central carbohydrate metabolism pathways of T. maritima are activated at higher temperatures.
PMCID: PMC3465335  PMID: 23071576
14.  Ultrastructural Modifications in the Mitochondria of Hypoxia-Adapted Drosophila melanogaster 
PLoS ONE  2012;7(9):e45344.
Chronic hypoxia (CH) occurs under certain physiological or pathological conditions, including in people who reside at high altitude or suffer chronic cardiovascular or pulmonary diseases. As mitochondria are the predominant oxygen-consuming organelles to generate ATP through oxidative phosphorylation in cells, their responses, through structural or molecular modifications, to limited oxygen supply play an important role in the overall functional adaptation to hypoxia. Here, we report the adaptive mitochondrial ultrastructural modifications and the functional impacts in a recently generated hypoxia-adapted Drosophila melanogaster strain that survives severe, otherwise lethal, hypoxic conditions. Using electron tomography, we discovered increased mitochondrial volume density and cristae abundance, yet also cristae fragmentation and a unique honeycomb-like structure in the mitochondria of hypoxia-adapted flies. The homeostatic levels of adenylate and energy charge were similar between hypoxia-adapted and naïve control flies and the hypoxia-adapted flies remained active under severe hypoxia as quantified by negative geotaxis behavior. The equilibrium ATP level was lower in hypoxia-adapted flies than those of the naïve controls tested under severe hypoxia that inhibited the motion of control flies. Our results suggest that the structural rearrangement in the mitochondria of hypoxia-adapted flies may be an important adaptive mechanism that plays a critical role in preserving adenylate homeostasis and metabolism as well as muscle function under chronic hypoxic conditions.
PMCID: PMC3446896  PMID: 23028948
15.  Regular Patterns for Proteome-Wide Distribution of Protein Abundance across Species 
PLoS ONE  2012;7(3):e32423.
A proteome of the bio-entity, including cell, tissue, organ, and organism, consists of proteins of diverse abundance. The principle that determines the abundance of different proteins in a proteome is of fundamental significance for an understanding of the building blocks of the bio-entity. Here, we report three regular patterns in the proteome-wide distribution of protein abundance across species such as human, mouse, fly, worm, yeast, and bacteria: in most cases, protein abundance is positively correlated with the protein's origination time or sequence conservation during evolution; it is negatively correlated with the protein's domain number and positively correlated with domain coverage in protein structure, and the correlations became stronger during the course of evolution; protein abundance can be further stratified by the function of the protein, whereby proteins that act on material conversion and transportation (mass category) are more abundant than those that act on information modulation (information category). Thus, protein abundance is intrinsically related to the protein's inherent characters of evolution, structure, and function.
PMCID: PMC3302874  PMID: 22427835
16.  Expanding role of ubiquitination in NF-κB signaling 
Cell Research  2010;21(1):6-21.
Best known for its role in targeting protein degradation by the proteasome, ubiquitin modification has also emerged as an important mechanism that regulates cell signaling through proteasome-independent mechanisms. The role of ubiquitin as a versatile signaling tag is characteristically illustrated in the NF-κB pathways, which regulate a variety of physiological and pathological processes in response to diverse stimuli. Here, we review the role of ubiquitination in different steps of the NF-κB signaling cascades, focusing on recent advances in understanding the mechanisms of protein kinase activation by polyubiquitin chains in different pathways that converge on NF-κB.
PMCID: PMC3193409  PMID: 21135871
NF-κB; ubiquitin; TAK1; IKK; TRAFs
17.  Expanding Role of Ubiquitination in NF-κB Signaling 
Cell research  2010;21(1):6-21.
Best known for its role in targeting protein degradation to the proteasome, ubiquitin modification has also emerged as an important mechanism that regulates cell signaling through proteasome-independent mechanisms. The role of ubiquitin as a versatile signaling tag is characteristically illustrated in the NF-κB pathways, which regulate a variety of physiological and pathological processes in response to diverse stimuli. Here we review the role of ubiquitination in different steps of the NF-κB signaling cascades, focusing on recent advances in understanding the mechanisms of protein kinase activation by polyubiquitin chains in different pathways that converge on NF-κB.
PMCID: PMC3193409  PMID: 21135871
18.  Identification and validation of rice reference proteins for western blotting 
Journal of Experimental Botany  2011;62(14):4763-4772.
Studies of rice protein expression have increased considerably with the development of rice functional genomics. In order to obtain reliable expression results in western blotting, information on appropriate reference proteins is necessary for data normalization. To date, no published study has identified and systematically validated reference proteins suitable for the investigation of rice protein expression. In this study, nine candidate proteins were selected and their specific antibodies were obtained through immunization of rabbits with either recombinant proteins expressed in Escherichia coli or synthesized peptides. Western blotting was carried out to detect the expression of target proteins in a set of 10 rice samples representing different rice tissues/organs at different developmental stages. The expression stability of the proteins was analysed using geNorm and Microcal Origin 6.0 software. The results indicated that heat shock protein (HSP) and elongation factor 1-α (eEF-1α) were the most constantly expressed among all rice proteins tested throughout all developmental stages, while the proteins encoded by conventional internal reference genes fluctuated in amount. Comparison among the profiling of translation and transcription [expressed sequence tags (EST) and massively parallel signature sequencing (MPSS)] revealed that a correlation existed. Based on the standard curves derived from the antigen–antibody reaction, the concentrations of HSP and eEF-1α proteins in rice leaves were ∼0.12%. Under the present experimental conditions, the lower limits of detection for HSP and eEF-1α proteins in rice were 0.24 ng and 0.06 ng, respectively. In conclusion, the reference proteins selected in this study, and the corresponding antibodies, can be used in qualitative and quantitative analysis of rice proteins.
PMCID: PMC3192993  PMID: 21705388
Antibody-based proteomics; rice (Oryza sativa L.); reference gene; reference protein; western blotting
19.  Regulation of Galactose Metabolism through the HisK:GalR Two-Component System in Thermoanaerobacter tengcongensis▿ †  
Journal of Bacteriology  2010;192(17):4311-4316.
Thermoanaerobacter tengcongensis could utilize galactose as a carbon source via the enzymes encoded by a novel gal operon, whose regulation mechanism has yet to be elucidated. We propose here that the gal operon in T. tengcongensis is regulated through a HisK:GalR two-component system. By using radioactive isotope assay and genetic analysis, we found that the kinase of this system, HisK, is phosphorylated by ATP, and the regulator, GalR, accepts a phosphoryl group during phosphorelay, in which the phosphoryl group at HisK-His-259 is transferred to GalR-Asp-56. Two-dimensional electrophoresis, followed by Western blotting, revealed that phosphorylation status of GalR is uniquely dependent on the galactose stimulus in vivo. Furthermore, DNA pulldown assays demonstrated that the phosphorylated GalR prefers binding to the operator DNA O2, whereas the unphosphorylated GalR to O1. A model of HisK:GalR is proposed to explain how galactose mediates the expression of the gal operon in T. tengcongensis.
PMCID: PMC2937391  PMID: 20581213
20.  Acrolein Consumption Induces Systemic Dyslipidemia and Lipoprotein Modification 
Aldehydes such as acrolein are ubiquitous pollutants present in automobile exhaust, cigarette, wood, and coal smoke. Such aldehydes are also constituents of several food substances and are present in drinking water, irrigation canals, and effluents from manufacturing plants. Oral intake represents the most significant source of exposure to acrolein and related aldehydes. To study the effects of short-term oral exposure to acrolein on lipoprotein levels and metabolism, adult mice were gavage fed 0.1 to 5 mg acrolein/kg bwt and changes in plasma lipoproteins were assessed. Changes in hepatic gene expression related to lipid metabolism and cytokines were examined by qRT-PCR analysis. Acrolein feeding did not affect body weight, BUN, plasma creatinine, electrolytes, cytokines or liver enzymes, but increased plasma cholesterol and triglycerides. Similar results were obtained with apoE-null mice. Plasma lipoproteins from acrolein-fed mice showed altered electrophoretic mobility on agarose gels. Chromatographic analysis revealed elevated VLDL cholesterol, phospholipids, and triglycerides levels with little change in LDL or HDL. NMR analysis indicated shifts from small to large VLDL and from large to medium-small LDL with no change in the size of HDL particles. Increased plasma VLDL was associated with a significant decrease in post-heparin plasma hepatic lipase activity and a decrease in hepatic expression of hepatic lipase. These observations suggest that oral exposure to acrolein could induce or exacerbate systemic dyslipidemia and thereby contribute to cardiovascular disease risk.
PMCID: PMC2922677  PMID: 20034506
acute phase response; aldehyde; cholesterol; hepatic lipase; lipoproteins; triglycerides
21.  Key Role of Ubc5 and Lysine-63 Polyubiquitination in Viral Activation of IRF3 
Molecular cell  2009;36(2):315-325.
The mitochondrial antiviral signaling protein (MAVS; also known as IPS-1, VISA and CARDIF) is essential for innate immune response against RNA viruses. MAVS transduces signals from the cytosolic RIG-I-like receptors, which bind to viral RNAs, but how MAVS activates downstream transcription factors such as IRF3 to induce type-I interferons is not well understood. We have established a cell-free system in which mitochondria derived from virus-infected cells activates IRF3 in the cytosol. Fractionation of the cytosol led to the identification of Ubc5 as a ubiquitin-conjugating enzyme (E2) required for IRF3 activation. Using an inducible RNAi strategy, we demonstrate that catalytically active Ubc5 is required for IRF3 activation by viral infection. The activation of IRF3 also requires two ubiquitin-binding domains of NEMO. Furthermore, we show that replacement of endogenous ubiquitin with its K63R mutant abolishes viral activation of IRF3, demonstrating that K63 polyubiquitination plays a key role in IRF3 activation.
PMCID: PMC2779157  PMID: 19854139
22.  A comprehensive crop genome research project: the Superhybrid Rice Genome Project in China 
In May 2000, the Beijing Institute of Genomics formally announced the launch of a comprehensive crop genome research project on rice genomics, the Chinese Superhybrid Rice Genome Project. SRGP is not simply a sequencing project targeted to a single rice (Oryza sativa L.) genome, but a full-swing research effort with an ultimate goal of providing inclusive basic genomic information and molecular tools not only to understand biology of the rice, both as an important crop species and a model organism of cereals, but also to focus on a popular superhybrid rice landrace, LYP9. We have completed the first phase of SRGP and provide the rice research community with a finished genome sequence of an indica variety, 93-11 (the paternal cultivar of LYP9), together with ample data on subspecific (between subspecies) polymorphisms, transcriptomes and proteomes, useful for within-species comparative studies. In the second phase, we have acquired the genome sequence of the maternal cultivar, PA64S, together with the detailed catalogues of genes uniquely expressed in the parental cultivars and the hybrid as well as allele-specific markers that distinguish parental alleles. Although SRGP in China is not an open-ended research programme, it has been designed to pave a way for future plant genomics research and application, such as to interrogate fundamentals of plant biology, including genome duplication, polyploidy and hybrid vigour, as well as to provide genetic tools for crop breeding and to carry along a social burden—leading a fight against the world's hunger. It began with genomics, the newly developed and industry-scale research field, and from the world's most populous country. In this review, we summarize our scientific goals and noteworthy discoveries that exploit new territories of systematic investigations on basic and applied biology of rice and other major cereal crops.
PMCID: PMC2435568  PMID: 17331896
rice; genome; transcriptome; proteome; hybrid vigour
23.  The Genomes of Oryza sativa: A History of Duplications 
Yu, Jun | Wang, Jun | Lin, Wei | Li, Songgang | Li, Heng | Zhou, Jun | Ni, Peixiang | Dong, Wei | Hu, Songnian | Zeng, Changqing | Zhang, Jianguo | Zhang, Yong | Li, Ruiqiang | Xu, Zuyuan | Li, Shengting | Li, Xianran | Zheng, Hongkun | Cong, Lijuan | Lin, Liang | Yin, Jianning | Geng, Jianing | Li, Guangyuan | Shi, Jianping | Liu, Juan | Lv, Hong | Li, Jun | Wang, Jing | Deng, Yajun | Ran, Longhua | Shi, Xiaoli | Wang, Xiyin | Wu, Qingfa | Li, Changfeng | Ren, Xiaoyu | Wang, Jingqiang | Wang, Xiaoling | Li, Dawei | Liu, Dongyuan | Zhang, Xiaowei | Ji, Zhendong | Zhao, Wenming | Sun, Yongqiao | Zhang, Zhenpeng | Bao, Jingyue | Han, Yujun | Dong, Lingli | Ji, Jia | Chen, Peng | Wu, Shuming | Liu, Jinsong | Xiao, Ying | Bu, Dongbo | Tan, Jianlong | Yang, Li | Ye, Chen | Zhang, Jingfen | Xu, Jingyi | Zhou, Yan | Yu, Yingpu | Zhang, Bing | Zhuang, Shulin | Wei, Haibin | Liu, Bin | Lei, Meng | Yu, Hong | Li, Yuanzhe | Xu, Hao | Wei, Shulin | He, Ximiao | Fang, Lijun | Zhang, Zengjin | Zhang, Yunze | Huang, Xiangang | Su, Zhixi | Tong, Wei | Li, Jinhong | Tong, Zongzhong | Li, Shuangli | Ye, Jia | Wang, Lishun | Fang, Lin | Lei, Tingting | Chen, Chen | Chen, Huan | Xu, Zhao | Li, Haihong | Huang, Haiyan | Zhang, Feng | Xu, Huayong | Li, Na | Zhao, Caifeng | Li, Shuting | Dong, Lijun | Huang, Yanqing | Li, Long | Xi, Yan | Qi, Qiuhui | Li, Wenjie | Zhang, Bo | Hu, Wei | Zhang, Yanling | Tian, Xiangjun | Jiao, Yongzhi | Liang, Xiaohu | Jin, Jiao | Gao, Lei | Zheng, Weimou | Hao, Bailin | Liu, Siqi | Wang, Wen | Yuan, Longping | Cao, Mengliang | McDermott, Jason | Samudrala, Ram | Wang, Jian | Wong, Gane Ka-Shu | Yang, Huanming
PLoS Biology  2005;3(2):e38.
We report improved whole-genome shotgun sequences for the genomes of indica and japonica rice, both with multimegabase contiguity, or almost 1,000-fold improvement over the drafts of 2002. Tested against a nonredundant collection of 19,079 full-length cDNAs, 97.7% of the genes are aligned, without fragmentation, to the mapped super-scaffolds of one or the other genome. We introduce a gene identification procedure for plants that does not rely on similarity to known genes to remove erroneous predictions resulting from transposable elements. Using the available EST data to adjust for residual errors in the predictions, the estimated gene count is at least 38,000–40,000. Only 2%–3% of the genes are unique to any one subspecies, comparable to the amount of sequence that might still be missing. Despite this lack of variation in gene content, there is enormous variation in the intergenic regions. At least a quarter of the two sequences could not be aligned, and where they could be aligned, single nucleotide polymorphism (SNP) rates varied from as little as 3.0 SNP/kb in the coding regions to 27.6 SNP/kb in the transposable elements. A more inclusive new approach for analyzing duplication history is introduced here. It reveals an ancient whole-genome duplication, a recent segmental duplication on Chromosomes 11 and 12, and massive ongoing individual gene duplications. We find 18 distinct pairs of duplicated segments that cover 65.7% of the genome; 17 of these pairs date back to a common time before the divergence of the grasses. More important, ongoing individual gene duplications provide a never-ending source of raw material for gene genesis and are major contributors to the differences between members of the grass family.
Comparative genome sequencing of indica and japonica rice reveals that duplication of genes and genomic regions has played a major part in the evolution of grass genomes
PMCID: PMC546038  PMID: 15685292

Results 1-23 (23)