It is essential that the genome be passed faithfully from parents to their offspring. Threats to faithful genome transmission come from limitations on the fidelity of replication, errors in chromosome segregation, and from the deleterious activity of parasitic genetic elements, transposons, which propagate by increasing their copy numbers in germ cell genomes. The challenge of transposon control is formidable. In Drosophila, more than 200 different elements are distributed among highly divergent families. These elements use different mobilization strategies and share no universal proteins or cofactors. Thus, the host must somehow discriminate this diversity of elements from protein coding genes and selectively silence the former. Over the past 6 years, we have come to understand that the piRNA pathway plays a critical role in reproductive tissues, embodying an essential defense mechanism against mobile genetic elements. Studies, mainly in Drosophila and mice, have established a molecular framework for how the piRNA pathway operates and have implicated a growing list of protein cofactors in its various stages. While we have produced a coarse model for piRNA production and for the mechanisms by which the pathway silences transposons, we are only just beginning to understand many of the molecular events that form the mechanistic basis of this innate immune system Our goal in this proposal is to address three key, outstanding issues. First, we wish to understand how the definition of a transposon is established in the form of a piRNA repertoire. This entails deciphering the regulation of piRNA generative loci, the mechanisms which mark RNAs to be processed into piRNAs, and the mechanics of piRNA biogenesis. Second, we will uncover the biochemistry of target repression by Piwi protein/piRNA complexes at both the transcriptional and post-transcriptional levels. Third, will probe the functions of maternally inherited piRNAs and their roles in germ cells and in the soma. By accomplishing these aims, we will contribute to the understanding of one of the most deeply rooted biological imperatives, the need to conserve the integrity of the germ line!

Public Health Relevance

It is essential that the genome be passed faithfully and intact from parents to their offspring. We have discovered a mechanism by which the genomes within the germ cells of virtually all animals are protected against damage by parasitic genetic elements. The goal of this proposal is to understand how this mechanism operates and to probe the full range of its biological functions.

Agency
National Institute of Health (NIH)
Type
Method to Extend Research in Time (MERIT) Award (R37)
Project #
5R37GM062534-15
Application #
8725675
Study Section
Molecular Genetics A Study Section (MGA)
Program Officer
Bender, Michael T
Project Start
Project End
Budget Start
Budget End
Support Year
15
Fiscal Year
2014
Total Cost
Indirect Cost
Name
Cold Spring Harbor Laboratory
Department
Type
DUNS #
City
Cold Spring Harbor
State
NY
Country
United States
Zip Code
11724
Fagegaltier, Delphine; Falciatori, Ilaria; Czech, Benjamin et al. (2016) Oncogenic transformation of Drosophila somatic cells induces a functional piRNA pathway. Genes Dev 30:1623-35
Goh, Wee Siong Sho; Falciatori, Ilaria; Tam, Oliver H et al. (2015) piRNA-directed cleavage of meiotic transcripts regulates spermatogenesis. Genes Dev 29:1032-44
Perkins, Lizabeth A; Holderbaum, Laura; Tao, Rong et al. (2015) The Transgenic RNAi Project at Harvard Medical School: Resources and Validation. Genetics 201:843-52
Wagenblast, Elvin; Soto, Mar; Gutiérrez-Ángel, Sara et al. (2015) A model of breast cancer heterogeneity reveals vascular mimicry as a driver of metastasis. Nature 520:358-62
Stein, Paula; Rozhkov, Nikolay V; Li, Fan et al. (2015) Essential Role for endogenous siRNAs during meiosis in mouse oocytes. PLoS Genet 11:e1005013
Yu, Yang; Gu, Jiaqi; Jin, Ying et al. (2015) Panoramix enforces piRNA-dependent cotranscriptional silencing. Science 350:339-42
Zhou, Xin; Battistoni, Giorgia; El Demerdash, Osama et al. (2015) Dual functions of Macpiwi1 in transposon silencing and stem cell maintenance in the flatworm Macrostomum lignano. RNA 21:1885-97
Wasik, Kaja; Gurtowski, James; Zhou, Xin et al. (2015) Genome and transcriptome of the regeneration-competent flatworm, Macrostomum lignano. Proc Natl Acad Sci U S A 112:12462-7
Knott, Simon R V; Maceli, Ashley R; Erard, Nicolas et al. (2014) A computational algorithm to predict shRNA potency. Mol Cell 56:796-807
Chang, Kenneth; Marran, Krista; Valentine, Amy et al. (2014) Generation of transgenic Drosophila expressing shRNAs in the miR-1 backbone. Cold Spring Harb Protoc 2014:

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