PIWI proteins and their associated small RNAs (piRNAs) are essential for male fertility in mammals. My long term goal is to understand the biology of piRNAs and their function in male fertility. Unknown mechanisms determine that some RNAs are loaded into PIWI and become piRNAs, while others are not. In this grant, I propose to study the structural and mechanistic factors that determine piRNA formation. I hypothesize that both (1) the unique structure of piRNA-producing loci and (2) specific post-transcriptional processing events target a transcript for piRNA production. Yet, neither is well understood. In the K99 phase of this proposal, I will study piRNA promoters, piRNA precursors, and piRNA processing intermediates. For these studies, I will develop new strategies for deep sequencing and fluorescent in-situ hybridization.I also propose to set up a cell-free system that recapitulates piRNA production for biochemical studies. In preliminary studies, I have already defined the transcription unit of piRNA producing loci, allowing their comparison with other genes, and I have observed a fragmentation event probably responsible for 5?? end formation of piRNAs, perhaps coupling with PIWI loading. In the R00 phase of this proposal, I will identify the elements and events that are necessary and sufficient for piRNA production, and dissect the steps and locations of piRNAs metabolism in the context of spermatogenesis. The proposed study to define a piRNA will help us to understand why piRNA mutant mice are infertile, leading to a better understanding of human male infertility.

Agency
National Institute of Health (NIH)
Institute
Eunice Kennedy Shriver National Institute of Child Health & Human Development (NICHD)
Type
Research Transition Award (R00)
Project #
4R00HD078482-03
Application #
8925978
Study Section
Special Emphasis Panel (NSS)
Program Officer
Moss, Stuart B
Project Start
2014-12-05
Project End
2017-11-30
Budget Start
2014-12-05
Budget End
2015-11-30
Support Year
3
Fiscal Year
2015
Total Cost
$249,000
Indirect Cost
$86,785
Name
University of Rochester
Department
Biochemistry
Type
Schools of Dentistry
DUNS #
041294109
City
Rochester
State
NY
Country
United States
Zip Code
14627
Sun, Yu Huining; Xie, Li Huitong; Zhuo, Xiaoyu et al. (2017) Domestic chickens activate a piRNA defense against avian leukosis virus. Elife 6:
Sharma, Upasna; Conine, Colin C; Shea, Jeremy M et al. (2016) Biogenesis and function of tRNA fragments during sperm maturation and fertilization in mammals. Science 351:391-396