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1.  Mutation-Specific RAS Oncogenicity Explains N-RAS Codon 61 Selection in Melanoma 
Cancer discovery  2014;4(12):1418-1429.
N-RAS mutation at codon 12, 13 or 61 is associated with transformation; yet, in melanoma, such alterations are nearly exclusive to codon 61. Here, we compared the melanoma susceptibility of an N-RasQ61R knock-in allele to similarly designed K-RasG12D and N-RasG12D alleles. With concomitant p16INK4a inactivation, K-RasG12D or N-RasQ61R expression efficiently promoted melanoma in vivo, whereas N-RasG12D did not. Additionally, N-RasQ61R mutation potently cooperated with Lkb1/Stk11 loss to induce highly metastatic disease. Functional comparisons of N-RasQ61R and N-RasG12D revealed little difference in the ability of these proteins to engage PI3K or RAF. Instead, N-RasQ61R showed enhanced nucleotide binding, decreased intrinsic GTPase activity and increased stability when compared to N-RasG12D. This work identifies a faithful model of human N-RAS mutant melanoma, and suggests that the increased melanomagenecity of N-RasQ61R over N-RasG12D is due to heightened abundance of the active, GTP-bound form rather than differences in the engagement of downstream effector pathways.
PMCID: PMC4258185  PMID: 25252692
NRAS; melanoma; codon-specific oncogene
2.  An epifluorescent attachment improves whole-plant digital photography of Arabidopsis thaliana expressing red-shifted green fluorescent protein 
AoB Plants  2012;2012:pls003.
Filter cubes made with machine-vision dichroic filters and illuminated with a royal blue light emitting diode can be used to produce an epifluorescent digital camera attachment that improves whole organism green fluorescent protein (GFP) photography. Mean pixel intensity responds linearly to purified GFP titration.
Background and aims
Studies have shown that levels of green fluorescent protein (GFP) leaf surface fluorescence are directly proportional to GFP soluble protein concentration in transgenic plants. However, instruments that measure GFP surface fluorescence are expensive. The goal of this investigation was to develop techniques with consumer digital cameras to analyse GFP surface fluorescence in transgenic plants.
Inexpensive filter cubes containing machine vision dichroic filters and illuminated with blue light-emitting diodes (LED) were designed to attach to digital single-lens reflex (SLR) camera macro lenses. The apparatus was tested on purified enhanced GFP, and on wild-type and GFP-expressing arabidopsis grown autotrophically and heterotrophically.
Principal findings
Spectrum analysis showed that the apparatus illuminates specimens with wavelengths between ∼450 and ∼500 nm, and detects fluorescence between ∼510 and ∼595 nm. Epifluorescent photographs taken with SLR digital cameras were able to detect red-shifted GFP fluorescence in Arabidopsis thaliana leaves and cotyledons of pot-grown plants, as well as roots, hypocotyls and cotyledons of etiolated and light-grown plants grown heterotrophically. Green fluorescent protein fluorescence was detected primarily in the green channel of the raw image files. Studies with purified GFP produced linear responses to both protein surface density and exposure time (H0: β (slope) = 0 mean counts per pixel (ng s mm−2)−1, r2 > 0.994, n = 31, P < 1.75 × 10−29).
Epifluorescent digital photographs taken with complementary metal-oxide-semiconductor and charge-coupled device SLR cameras can be used to analyse red-shifted GFP surface fluorescence using visible blue light. This detection device can be constructed with inexpensive commercially available materials, thus increasing the accessibility of whole-organism GFP expression analysis to research laboratories and teaching institutions with small budgets.
PMCID: PMC3296078  PMID: 22479674

Results 1-2 (2)