Project description:We investigated whether exposure to a captive environment during maturation influenced gamete DNA methylation for wild Atlantic Salmon individuals. We then investigated whether these parental effects were detectable in an F1 generation reared in a common environment. We associated DNA methylation with growth and fitness-related phenotypes and demonstrated that intergenerational effects of hatchery exposure during maturation of the parental generation influence fitness-related methylation patterns in the F1 generation.
Project description:The hypothesis that increased fitness within a selective environment must be accompanied by a loss of fitness in other non-selective environments leads to the notion of evolutionary tradeoffs. Experimental evolution provides an approach to test the existence of evolutionary tradeoffs, characterize their general quality, and reveal their genetic origins. To examine the underlying mechanism for a fitness trade-off, we constructed the evolutionary trajectories of Escherichia coli K-12 at increasing temperatures up to 45.3°C, and found diverging mutational histories that led to adaptive phenotypes with and without fitness trade-offs at low temperatures. We identified genetic changes in cellular respiration, iron metabolism and methionine biosynthesis that regulated gene expression to achieve thermal adaptation and determined the presence and absence of a fitness trade-off. Our results suggested that evolutionary trade-off could be generated by a regulatory protein mutation that was beneficial in the selective conditions but forced suboptimal proteome allocation under non-selective environments.
Project description:Conventional reverse genetic approaches for study of Plasmodium malaria parasite gene function are limited, or not applicable. Hence, new inducible systems are needed. Here we describe a method to control P. falciparum gene expression in which target genes bearing a glmS ribozyme in the 3M-bM-^@M-2 untranslated region (3M-bM-^@M-2-UTR) are efficiently knocked down in transgenic P. falciparum parasites in response to exogenous glucosamine (GlcN) inducer. Using reporter genes, we show that the glmS ribozyme cleaves reporter mRNA in vivo leading to reduction in mRNA expression following GlcN treatment. GlcN-induced ribozyme activation also led to efficient reduction of reporter protein, which could be rapidly reversed by removing the inducer. The glmS ribozyme was validated as a reverse-genetic tool by integration into the essential gene and antifolate drug target dihydrofolate reductase-thymidylate synthase (PfDHFR-TS). GlcN treatment of transgenic parasites led to rapid and efficient knockdown of PfDHFR-TS mRNA and protein. PfDHFR-TS knockdown led to a growth/arrest mutant phenotype and hypersensitivity to pyrimethamine. The glmS ribozyme is thus an important tool for study of P. falciparum essential genes and anti-malarial drug discovery. mRNA profiles were generated from 3D7 wild-type and DHFR-TS-GFP_glmS integrant parasites in untreated and treated with 10 mM Glucosamine conditions in duplicate.
Project description:rs12-06_a9-mrnonpolya - matr knockdown 1 - Mitochondrial transcriptome regulation and coordination with the nucleus - Following a previously established strategy (Val et al., 2011, Nucleic Acids Res. 39, 9262–9274), we express, from an estradiol-inducible nuclear transgene, a trans-cleaving ribozyme directed against the matR mitochondrial mRNA and associated as a trailor sequence to a tRNA mimic. The latter serves as a shuttle and ensures mitochondrial uptake of the chimeric RNA through the natural tRNA import pathway. In mitochondria, the ribozyme triggers cleavage and degradation of the target mRNA. The impact of the matR mRNA knockdown on the overall plant transcriptome. Control plants express either no ribozyme (C0a and C0b) or the shuttle RNA combined with a ribozyme that has no specific target in A. thaliana (SD).
Project description:AIMS To identify the underlying mechanism by which Vitamin D reduces colorectal cancer risk.
OBJECTIVES To demonstrate the effects of vitamin D supplementation on serum vitamin D levels.
To demonstrate dynamic changes in gene expression in response to vitamin D. To demonstrate the mechanism underlying the gene-environment interaction of vitamin D, susceptibility genetic variants (risk genes) and colorectal cancer.
Project description:A fitness landscape (FL) describes the genotype-fitness relationship in a given environment. To explain and predict evolution, it is imperative to measure the FL in multiple environments because the natural environment changes frequently. Using a high-throughput method that combines precise gene replacement with next-generation sequencing, we determine the in vivo FL of a yeast tRNA gene comprising over 23,000 genotypes in four environments. Although genotype-by-environment interaction (G×E) is abundantly detected, its pattern is so simple that we can transform an existing FL to that in a new environment with fitness measures of only a few genotypes in the new environment. Under each environment, we observe prevalent, negatively biased epistasis between mutations (G×G). Epistasis-by-environment interaction (G×G×E) is also prevalent, but trends in epistasis difference between environments are predictable. Our study thus reveals simple rules underlying seemingly complex FLs, opening the door to understanding and predicting FLs in general.
2018-03-23 | GSE111508 | GEO
Project description:The dynamic changes in small RNA contents during sperm epididymal transit
Project description:As part of an examination of a newly-evolved RNA polymerase ribozyme, 38-6, products of primer extension experiments using an RNA template encoding the hammerhead RNA endonuclease ribozyme, using 38-6 and its less active ancestor 24-3. These products were analyzed by next-generation sequencing to determine the rates of substitution, deletion, and insertion mutations for both polymerases.