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1.  Gene Network Analysis of Small Molecules with Autoimmune Disease Associated Genes Predicts a Novel Strategy for Drug Efficacy 
Autoimmunity reviews  2012;12(4):510-522.
Numerous genes/SNPs in autoimmune diseases (ADs) are identified through genome-wide association studies (GWAS) and likely to contribute in developing autoimmune phenotypes. Constructions of biologically meaningful pathways are necessary to determine how these genes interact each other and with other small molecules to develop various complex ADs phenotypes prior to beginning time-consuming rigorous experimentation. We have constructed biological pathways with genetically identified genes leading to shared ADs phenotypes. Various environmental and endogenous factors interact with these ADs associated genes suggesting their critical role in developing diseases and further association studies could be designed for assessing the role of these factors with risk allele in a specific gene. Additionally, existing drugs that have been used long before the identification of these genetically associated genes also interact with these newly associated genes. Thus advanced therapeutic strategies could be designed by grouping patients with risk allele(s) in particular genes that directly or closely interact with the specified drugs. This drug-susceptible gene network will not only increase our understanding about the additional molecular basis for effectiveness against these diseases but also which drug could be more effective for those patients carrying risk allele(s) in that gene. Additionally, we have also identified several interlinking genes in the pathways that could be used for designing future association studies.
doi:10.1016/j.autrev.2012.09.001
PMCID: PMC3577986  PMID: 23000205
2.  Confirmation of an Association Between rs6822844 at the IL2–IL21 Region and Multiple Autoimmune Diseases 
Arthritis and rheumatism  2010;62(2):323-329.
Objective
Autoimmune diseases often have susceptibility genes in common, indicating similar molecular mechanisms. Increasing evidence suggests that rs6822844 at the IL2–IL21 region is strongly associated with multiple autoimmune diseases in individuals of European descent. This study was undertaken to attempt to replicate the association between rs6822844 and 6 different immune-mediated diseases in non-European populations, and to perform disease-specific and overall meta-analyses using data from previously published studies.
Methods
We evaluated case–control associations between rs6822844 and celiac disease (CD) in subjects from Argentina; rheumatoid arthritis (RA), type 1 diabetes mellitus (DM), primary Sjögren's syndrome (SS), and systemic lupus erythematosus (SLE) in subjects from Colombia; and Behçet's disease (BD) in subjects from Turkey. Allele and gene distributions were compared between cases and controls. Meta-analyses were performed using data from the present study and previous studies.
Results
We detected significant associations of rs6822844 with SLE (P = 0.008), type 1 DM (P = 0.014), RA (P = 0.019), and primary SS (P = 0.033) but not with BD (P = 0.34) or CD (P = 0.98). We identified little evidence of population differentiation (FST = 0.01) within cases and controls from Argentina and Colombia, suggesting that association was not influenced by population substructure. Disease-specific meta-analysis indicated significant association for RA (Pmeta = 3.61 × 10–6), inflammatory bowel disease (IBD; Crohn's disease and ulcerative colitis) (Pmeta = 3.48 × 10–12), type 1 DM (Pmeta = 5.33 × 10–5), and CD (Pmeta = 5.30 × 10–3). Overall meta-analysis across all autoimmune diseases reinforced association with rs6822844 (23 data sets; Pmeta = 2.61 × 10–25, odds ratio 0.73 [95% confidence interval 0.69–0.78]).
Conclusion
Our results indicate that there is an association between rs6822844 and multiple auto-immune diseases in non-European populations. Meta-analysis results strongly reinforce this robust association across multiple autoimmune diseases in both European-derived and non-European populations.
doi:10.1002/art.27222
PMCID: PMC3028384  PMID: 20112382
3.  Isolation, in silico characterization and chromosomal localization of a group of cDNAs from ciliated epithelial cells after in vitro ciliogenesis 
Genome Biology  2001;2(7):research0026.1-research0026.9.
Background
Immotile cilia syndrome (ICS) or primary ciliary dyskinesia (PCD) is an autosomal recessive disorder in humans in which the beating of cilia and sperm flagella is impaired. Ciliated epithelial cell linings are present in many tissues. To understand ciliary assembly and motility, it is important to isolate those genes involved in the process.
Results
Total RNA was isolated from cultured ciliated nasal epithelial cells after in vitro ciliogenesis and expressed sequenced tags (ESTs) were generated. The functions and locations of 63 of these ESTs were derived by BLAST from two public databases. These ESTs are grouped into various classes. One group has high homology not only with the mitochondrial genome but also with one or more chromosomal DNAs, suggesting that very similar genes, or genes with very similar domains, are expressed from both mitochondrial and nuclear DNA. A second class comprises genes with complete homology with part of a known gene, suggesting that they are the same genes. A third group has partial homology with domains of known genes. A fourth group, constituting 33% of the ESTs characterized, has no significant homology with any gene or EST in the database.
Conclusions
We have shown that sufficient information about the location of ESTs could be derived electronically from the recently completed human genome sequences. This strategy of EST localization should be significantly useful for mapping and identification of new genes in the forthcoming human genome sequences with the vast number of ESTs in the dbEST database.
PMCID: PMC55323  PMID: 11516339
4.  Increased Risk of Lung Cancer Associated with a Functionally Impaired Polymorphic Variant of the Human DNA Glycosylase NEIL2 
DNA Repair  2012;11(6):570-578.
Human NEIL2, one of five oxidized base-specific DNA glycosylases, is unique in preferentially repairing oxidative damage in transcribed genes. Here we show that depletion of NEIL2 causes a 6- to 7-fold increase in spontaneous mutation frequency in the HPRT gene of the V79 Chinese hamster lung cell line. This prompted us to screen for NEIL2 variants in lung cancer patients’ genomic DNA. We identified several polymorphic variants, among which R103Q and R257L were frequently observed in lung cancer patients. We then characterized these variants biochemically, and observed a modest decrease in DNA glycosylase activity relative to the wild type (WT) only with the R257L mutant protein. However, in reconstituted repair assays containing WT NEIL2 or its R257L and R103Q variants together with other DNA base excision repair (BER) proteins (PNKP, Polβ, Lig IIIα and XRCC1) or using NEIL2-FLAG immunocomplexes, an ~ 5-fold decrease in repair was observed with the R257L variant compared to WT or R103Q NEIL2, apparently due to the R257L mutant’s lower affinity for other repair proteins, particularly Polβ. Notably, increased endogenous DNA damage was observed in NEIL2 variant (R257L)-expressing cells relative to WT cells. Taken together, our results suggest that the decreased DNA repair capacity of the R257L variant can induce mutations that lead to lung cancer development.
doi:10.1016/j.dnarep.2012.03.005
PMCID: PMC3361577  PMID: 22497777
5.  Admixture Mapping in Lupus Identifies Multiple Functional Variants within IFIH1 Associated with Apoptosis, Inflammation, and Autoantibody Production 
PLoS Genetics  2013;9(2):e1003222.
Systemic lupus erythematosus (SLE) is an inflammatory autoimmune disease with a strong genetic component. African-Americans (AA) are at increased risk of SLE, but the genetic basis of this risk is largely unknown. To identify causal variants in SLE loci in AA, we performed admixture mapping followed by fine mapping in AA and European-Americans (EA). Through genome-wide admixture mapping in AA, we identified a strong SLE susceptibility locus at 2q22–24 (LOD = 6.28), and the admixture signal is associated with the European ancestry (ancestry risk ratio ∼1.5). Large-scale genotypic analysis on 19,726 individuals of African and European ancestry revealed three independently associated variants in the IFIH1 gene: an intronic variant, rs13023380 [Pmeta = 5.20×10−14; odds ratio, 95% confidence interval = 0.82 (0.78–0.87)], and two missense variants, rs1990760 (Ala946Thr) [Pmeta = 3.08×10−7; 0.88 (0.84–0.93)] and rs10930046 (Arg460His) [Pdom = 1.16×10−8; 0.70 (0.62–0.79)]. Both missense variants produced dramatic phenotypic changes in apoptosis and inflammation-related gene expression. We experimentally validated function of the intronic SNP by DNA electrophoresis, protein identification, and in vitro protein binding assays. DNA carrying the intronic risk allele rs13023380 showed reduced binding efficiency to a cellular protein complex including nucleolin and lupus autoantigen Ku70/80, and showed reduced transcriptional activity in vivo. Thus, in SLE patients, genetic susceptibility could create a biochemical imbalance that dysregulates nucleolin, Ku70/80, or other nucleic acid regulatory proteins. This could promote antibody hypermutation and auto-antibody generation, further destabilizing the cellular network. Together with molecular modeling, our results establish a distinct role for IFIH1 in apoptosis, inflammation, and autoantibody production, and explain the molecular basis of these three risk alleles for SLE pathogenesis.
Author Summary
African-Americans (AA) are at increased risk of systemic lupus erythematosus (SLE), but the genetic basis of this risk increase is largely unknown. We used admixture mapping to localize disease-causing genetic variants that differ in frequency across populations. This approach is advantageous for localizing susceptibility genes in recently admixed populations like AA. Our genome-wide admixture scan identified seven admixture signals, and we followed the best signal at 2q22–24 with fine-mapping, imputation-based association analysis and experimental validation. We identified two independent coding variants and a non-coding variant within the IFIH1 gene associated with SLE. Together with molecular modeling, our results establish a distinct role for IFIH1 in apoptosis, inflammation, and autoantibody production, and explain the molecular basis of these three risk alleles for SLE pathogenesis.
doi:10.1371/journal.pgen.1003222
PMCID: PMC3575474  PMID: 23441136
6.  Evaluation of 19 Autoimmune Disease-associated Loci with Rheumatoid Arthritis in a Colombian Population: Evidence for Replication and Gene-Gene Interaction 
The Journal of rheumatology  2011;38(9):1866-1870.
Objective
Recent studies have identified several common genes associated with multiple autoimmune diseases that support the hypothesis of the presence of shared or general autoimmunity genes. However, most of this work has been performed in populations of white origin. The main objectives of this study are to replicate the genotype-phenotype correlation between 19 such variants and rheumatoid arthritis (RA), and to evaluate gene-gene interactions between these genes in individuals from an ethnically homogenous nonwhite Colombian population.
Methods
Nineteen single-nucleotide polymorphisms (SNP) from 16 genes/loci were genotyped in 353 RA cases and 368 controls. For each SNP, allelic and genotype-based association tests were applied to evaluate genotype-phenotype correlation. Permutation-based tests were used to validate the statistical significance. Gene-gene interactions were assessed by logistic regression.
Results
We replicated the genetic association with rs13277113 (p = 0.0009, OR 1.46) and rs2736340 (p = 0.0001, OR 1.63) from C8orf13-BLK (8p23.1, associated with RA and systemic lupus erythematosus), and rs763361 (p = 0.03) from CD226 (18q22.3, associated with multiple sclerosis and type 1 diabetes) in the Colombian population. The population-attributable risks were estimated as 27%, 34%, and 16% for rs13277113, rs2736340, and rs763361, respectively. We also detected evidence for gene-gene interaction between SNP in MMEL1 (rs3890745) and C80rf13-BLK (rs13277113; p = 0.0002).
Conclusion
Our results demonstrate that the IL2/IL21 region, C8orf13-BLK, and CD226 influence RA in Colombians, and RA shares some of the pathogenic mechanisms associated with other autoimmune diseases.
doi:10.3899/jrheum.110199
PMCID: PMC3170719  PMID: 21765104
RHEUMATOID ARTHRITIS; LATIN AMERICA; GENETIC ASSOCIATION; GENE-GENE INTERACTION
7.  Non-synonymous variant (Gly307Ser) in CD226 is associated with susceptibility to multiple autoimmune diseases 
Rheumatology (Oxford, England)  2010;49(7):1239-1244.
Objectives. Recently, a non-synonymous (Gly307Ser) variant, rs763361, in the CD226 gene was shown to be associated with multiple autoimmune diseases (ADs) in European Caucasian populations. However, shared autoimmunity with CD226 has not been evaluated in non-European populations. The aim of the present study is to assess the association of this single nucleotide polymorphism (SNP) with ADs in non-European populations.
Methods. To replicate this association in non-European populations, we evaluated case–control association between rs763361 and coeliac disease (CED) samples from Argentina; SLE, RA, type-1 diabetes (T1D) and primary SS (pSS) from Colombia; and SLE samples from China and Japan. We genotyped rs763361 and evaluated its genetic association with multiple ADs, using χ2-test. For each association, odds ratio (OR) and 95% CI were calculated.
Results. We show that rs763361 is significantly associated with Argentinean CED (P = 0.0009, OR = 1.60). We also observed a trend of possible association with Chinese SLE (P = 0.01, OR = 1.19), RA (P = 0.047, OR = 1.25), SLE (P = 0.0899, OR = 1.24) and pSS (P = 0.09, OR = 1.33) in Colombians. Meta-analyses for SLE (using our three populations) and T1D (our population and three published populations) yielded significant association with rs763361, P = 0.009 (OR = 1.16) and P = 1.1.46 × 10−9 (OR = 1.14), respectively.
Conclusions. Our results demonstrate that the coding variant rs763361 in CD226 gene is associated with multiple ADs in non-European populations.
doi:10.1093/rheumatology/kep470
PMCID: PMC2909799  PMID: 20338887
CD226; Autoimmunity; Latin-America; Asia
8.  ITGAM coding variant (rs1143679) influences the risk of renal disease, discoid rash, and immunologic manifestations in lupus patients with European ancestry 
Annals of the rheumatic diseases  2009;69(7):1329-1332.
Purpose
We hypothesized that the coding variant (R77H), rs1143679, within ITGAM could predict specific clinical manifestations associated with lupus.
Method
To assess genetic association, 2366 lupus cases and 2931 unaffected controls with European ancestry were analyzed. Lupus patients were coded by the presence or absence of individual ACR criteria. Logistic regression and Pearson chi-square tests were used to assess statistical significance.
Results
First, for overall case-control analysis, we detected highly significant (p=2.22×10−21, OR=1.73) association. Second, using case-only analysis we detected significant association with renal criteria (p=0.0003), discoid rash (p=0.02), and immunologic criteria (p=0.04). Third, we compared them with healthy controls, the association became stronger for renal (p=4.69×10−22, OR=2.15), discoid (p=1.77×10−14, OR=2.03), and immunologic (p=3.49×10−22, OR = 1.86) criteria. Risk allele frequency increased from 10.6% (controls) to 17.0% (lupus), 20.4% (renal), 18.1% (immunologic), and 19.5% (discoid).
Conclusion
These results demonstrated a strong association between the risk allele (A) at rs1143679 and renal disease, discoid rash, and immunological manifestations of lupus.
doi:10.1136/ard.2009.120543
PMCID: PMC2891778  PMID: 19939855
9.  Mutator Phenotype of Mammalian Cells Due to Deficiency of NEIL1 DNA Glycosylase, An Oxidized Base-Specific Repair Enzyme 
DNA repair  2008;7(8):1213-1220.
The recently characterized NEIL1 and NEIL2 are distinct from the previously characterized mammalian DNA glycosylases (OGG1 and NTH1) involved in repair of oxidized bases because of the NEILs’ preference for excising base lesions from single-stranded DNA present in bubble and fork structures. OGG1 and NTH1 are active only with duplex DNA. This raises the possibility that NEILs function in the repair of base lesions during DNA replication and/or transcription. S-phase- specific activation of only NEIL1 suggests its preferential involvement in repair during DNA replication. Here we show that antisense oligonucleotides specific for human or Chinese hamster NEIL1 decreased in vivo NEIL1 levels by 70–80%, concomitant with increased oxidative damage in the genome. Moreover, NEIL1 downregulation enhanced spontaneous mutation in the HPRT locus by about 3-fold in both Chinese hamster V79 and human bronchial A549 cell lines. The mutant frequency was further enhanced (7- to 8-fold) under oxidative stress. The majority of both spontaneous and induced mutations occurred at A•T base pairs, indicating that oxidized A and/or T are NEIL1’s preferred in vivo substrates. NEIL1 thus plays a distinct and important role in repairing endogenous and induced mutagenic oxidized bases, and hence in maintaining the functional integrity of mammalian genomes.
doi:10.1016/j.dnarep.2008.03.025
PMCID: PMC2567110  PMID: 18495559
BER; HPRT; mutagenesis; NEIL1; oxidative stress
10.  Regulatory Role of Human AP-Endonuclease (APE1/Ref-1) in YB-1-Mediated Activation of the Multidrug Resistance Gene MDR1▿ †  
Molecular and Cellular Biology  2008;28(23):7066-7080.
Human AP-endonuclease (APE1/Ref-1), a central enzyme involved in the repair of oxidative base damage and DNA strand breaks, has a second activity as a transcriptional regulator that binds to several trans-acting factors. APE1 overexpression is often observed in tumor cells and confers resistance to various anticancer drugs; its downregulation sensitizes tumor cells to such agents. Because the involvement of APE1 in repairing the DNA damage induced by many of these drugs is unlikely, drug resistance may be linked to APE1's transcriptional regulatory function. Here, we show that APE1, preferably in the acetylated form, stably interacts with Y-box-binding protein 1 (YB-1) and enhances its binding to the Y-box element, leading to the activation of the multidrug resistance gene MDR1. The enhanced MDR1 level due to the ectopic expression of wild-type APE1 but not of its nonacetylable mutant underscores the importance of APE1's acetylation in its coactivator function. APE1 downregulation sensitizes MDR1-overexpressing tumor cells to cisplatin or doxorubicin, showing APE1's critical role in YB-1-mediated gene expression and, thus, drug resistance in tumor cells. A systematic increase in both APE1 and MDR1 expression was observed in non-small-cell lung cancer tissue samples. Thus, our study has established the novel role of the acetylation-mediated transcriptional regulatory function of APE1, making it a potential target for the drug sensitization of tumor cells.
doi:10.1128/MCB.00244-08
PMCID: PMC2593380  PMID: 18809583
11.  Poly purine.pyrimidine sequences upstream of the beta-galactosidase gene affect gene expression in Saccharomyces cerevisiae 
Background
Poly purine.pyrimidine sequences have the potential to adopt intramolecular triplex structures and are overrepresented upstream of genes in eukaryotes. These sequences may regulate gene expression by modulating the interaction of transcription factors with DNA sequences upstream of genes.
Results
A poly purine.pyrimidine sequence with the potential to adopt an intramolecular triplex DNA structure was designed. The sequence was inserted within a nucleosome positioned upstream of the β-galactosidase gene in yeast, Saccharomyces cerevisiae, between the cycl promoter and gal 10Upstream Activating Sequences (UASg). Upon derepression with galactose, β-galactosidase gene expression is reduced 12-fold in cells carrying single copy poly purine.pyrimidine sequences. This reduction in expression is correlated with reduced transcription. Furthermore, we show that plasmids carrying a poly purine.pyrimidine sequence are not specifically lost from yeast cells.
Conclusion
We propose that a poly purine.pyrimidine sequence upstream of a gene affects transcription. Plasmids carrying this sequence are not specifically lost from cells and thus no additional effort is needed for the replication of these sequences in eukaryotic cells.
doi:10.1186/1471-2199-2-11
PMCID: PMC59624  PMID: 11696239
12.  Assembling and gap filling of unordered genome sequences through gene checking 
Genome Biology  2001;2(9):preprint0008.1-preprint0008.11.
Background
The first draft of human genome sequencing is complete. A large amount of DNA sequences are already available in the database but these are not ordered and assembled. In many cases, these sequences are shorter sequences (ranging from 10kb to 100kb) and are separated by "NNNNNN". Also a considerable amount of gaps are to be filled in the subsequent years. Even after generating raw data, properly ordered, finished available sequences, are enormous tasks and expected to take another 2 years.
Results
Here, we describe a simple way to order random genome sequences and to trace gaps. These gaps could be filled by subsequent hybridizations and sequencing. These could be achieved by a simple method by three steps. 1) Selection of large cDNAs in the database (from lower organisms to human). 2) Blasting with these large cDNAs to the unordered human genomic sequences (raw BAC DNA sequences or large DNA fragments) . 3) Ordering these BACs DNA sequences or large DNA fragments based on the homology with cDNA sequences to maintain the continuity of exonic sequences. Homologous exons could also be taken into account on the basis of evolutionary conservacy when other organism's sequence except human, would be used for blasting. Any discontinuity in the exonic sequences denote possible gaps in between two BACs or two sequences.
Conclusions
In this way a large number of BACs could be arranged. Subsequently gaps could be traced and filled by further hybridizations and sequencing.
doi:10.1186/gb-2001-2-9-preprint0008
PMCID: PMC4073045

Results 1-12 (12)