Elucidation of molecular mechanisms of the primary piRNA pathway

2016 Fiscal Year Final Research Report

• Project/Area Number: 15H05585
• Research Category: Grant-in-Aid for Young Scientists (A)
• Allocation Type: Single-year Grants
• Research Field: Molecular biology
• Research Institution: The University of Tokyo
• Principal Investigator: Ishizu Hirotsugu 東京大学, 大学院理学系研究科(理学部), 助教 (40574588)
• Project Period (FY): 2015-04-01 – 2017-03-31
• Keywords: piRNA / Piwi / CRISPR / tj / 翻訳

Outline of Final Research Achievements

piRNAs in Drosophila ovarian somatic cells (OSCs) are generated only through the primary processing pathway and are loaded onto Piwi, a member of PIWI proteins. piRNAs arise mainly from intergenic repetitive elements including transposable elements (TEs) and their remnants. Besides TEs, a subset of mRNAs gives rise to ‘genic piRNAs’, mainly from their 3’ UTR, including Traffic jam (Tj) mRNA. Recently, we have identified a cis-acting 100-nt fragment in the Tj 3' UTR that is sufficient for producing artificial piRNAs from unintegrated DNA. SHAPE analysis showed that the Tj-cis element formed a specific structure. We found that point mutations within the cis element, which disrupted the proper structure, caused a failure of piRNA biogenesis from the downstream region. These results indicate that the piRNA cis element is characterized by RNA secondary structures.

Free Research Field

分子生物学