Transposon dependent gene silencing in Drosophila

点击翻译按钮获取中文摘要

In eukaryote genomes, including humans, there are large numbers of transposable elements. These short DNA segments can move around the genome, rearrange large segments of chromosomes, and alter the expression of genes. The genetic and molecular mechanism(s) of their role in gene expression is not well understood, however, it is clear that they function via proteins that regulate chromatin structure. The description of these proteins and their functions is a prerequisite for understanding the mechanisms involved. Towards understanding these mechanisms we have developed a simple genetic system in the common Fruit Fly, Drosophila, to examine the role of a transposon, the P element, in the regulation of an adjacent reporter gene. Drosophila is a proven, excellent model organism. Historically, the advantages of the research tools in genetic, cellular, and developmental biology have provided valuable insight into a wide variety of biological and biochemical mechanisms. Our past research has shown that the P element repressor protein induces gene silencing. The molecular mechanism involves specific heterochromatic proteins binding to DNA. The details of the protein-protein and protein-DNA interactions are as yet unknown. We intend to examine the mechanism of how the P element repressor acts to cause location specific gene silencing. Using established methods, we will put the repressor protein gene (and others we have identified), in modified forms, into various GAL4-UAS expression constructs and transform them back into the germline of Drosophila to evaluate their effects. We hypothesize that by examining the effects of modified (mutant) forms we can identify functional domains in these proteins and derive the molecular mechanism(s) of this gene silencing. These domains can be confirmed by other methods such as ChIP and co-immunoprecipitation. The domain interactions between and among the proteins will define the molecular events constituting the mechanism. By identifying the molecular mechanism of transposon mediated gene silencing in a model organism, such as Drosophila, we can apply this knowledge to other eukaryotes in areas such as medicine, agriculture, and biotechnology.