MicroRNAs (miRNAs) are ~22 nt long, single-stranded RNA guides that regulate the expression of plant and animal genes. miRNAs regulate more than one-third of all human genes, and inappropriate production or loss of microRNAs in specific types of cells can cause human disease. Thus, a better understanding of how miRNAs are made and how they function will advance knowledge of the causes of and potential treatments for human diseases. The goal of these studies is to understand how the information in these tiny riboregulators and their precursors is used by higher eukaryotes to ensure the accurate production of mature miRNAs, their loading into functional protein complexes, and the appropriate type of regulation of authentic mRNA targets. miRNAs were discovered in 1993 and the study of their biogenesis began in 2001 with the discovery that the multi-domain ribonuclease III (RNase III) enzyme Dicer converts miRNA precursors (pre-miRNAs) into mature miRNAs. In the intervening years, the number of known and predicted miRNAs has grown from two to more than 10,000. As a class, miRNAs may rival transcription factors in their importance for orchestrating changes in gene expression. This proposal uses Drosophila melanogaster to study the biogenesis and assembly of miRNAs into functional complexes, as well as the regulation of mRNA targets by miRNAs, because these processes are closely conserved between flies and humans. A combination of cell-free biochemical methods, cell culture experiments, cell biology, and in vivo genetics in flies will be used to dissect the mechanism and biological importance of the miRNA pathway. What is learned in flies is tested in mammalian cell extracts, and in vitro in cultured human and mouse cell lines to identify where these processes are conserved and where they diverge between flies and mammals. The next grant period will continue efforts to understand miRNA biogenesis and function. The project seeks to identify the proteins and protein complexes required to produce miRNA from pre-miRNA and to determine how these proteins function in miRNA maturation;determine how small RNAs are sorted into complexes containing different Argonaute proteins;determine how miRNA stability is controlled;and identify the enzymes that tail and trim Ago1-bound miRNAs.

Public Health Relevance

MicroRNAs regulate more than one-third of all human genes, and inappropriate production or loss of these tiny RNAs in specific types of cells can cause human disease. The Drosophila microRNA pathway is highly similar to its mammalian counterpart, so what is learned in these studies will advance our understanding of microRNAs in humans. Thus, the proposed studies promise to contribute to a better understanding of and therapy for human diseases.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
5R01GM065236-12
Application #
8601093
Study Section
Molecular Genetics C Study Section (MGC)
Program Officer
Bender, Michael T
Project Start
2003-01-01
Project End
2014-12-31
Budget Start
2014-01-01
Budget End
2014-12-31
Support Year
12
Fiscal Year
2014
Total Cost
$453,482
Indirect Cost
$177,809
Name
University of Massachusetts Medical School Worcester
Department
Biochemistry
Type
Schools of Medicine
DUNS #
603847393
City
Worcester
State
MA
Country
United States
Zip Code
01655
Gainetdinov, Ildar; Colpan, Cansu; Arif, Amena et al. (2018) A Single Mechanism of Biogenesis, Initiated and Directed by PIWI Proteins, Explains piRNA Production in Most Animals. Mol Cell 71:775-790.e5
Chou, Min-Te; Han, Bo W; Hsiao, Chiung-Po et al. (2015) Tailor: a computational framework for detecting non-templated tailing of small silencing RNAs. Nucleic Acids Res 43:e109
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Han, Bo W; Wang, Wei; Li, Chengjian et al. (2015) Noncoding RNA. piRNA-guided transposon cleavage initiates Zucchini-dependent, phased piRNA production. Science 348:817-21
Fukunaga, Ryuya; Colpan, Cansu; Han, Bo W et al. (2014) Inorganic phosphate blocks binding of pre-miRNA to Dicer-2 via its PAZ domain. EMBO J 33:371-84
Wang, Wei; Yoshikawa, Mayu; Han, Bo W et al. (2014) The initial uridine of primary piRNAs does not create the tenth adenine that Is the hallmark of secondary piRNAs. Mol Cell 56:708-16
Zhang, Zhao; Koppetsch, Birgit S; Wang, Jie et al. (2014) Antisense piRNA amplification, but not piRNA production or nuage assembly, requires the Tudor-domain protein Qin. EMBO J 33:536-9
Flores-Jasso, C Fabian; Salomon, William E; Zamore, Phillip D (2013) Rapid and specific purification of Argonaute-small RNA complexes from crude cell lysates. RNA 19:271-9

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