Title

Heterotypic piRNA Ping-Pong requires qin, a protein with both E3 ligase and Tudor domains

UMMS Affiliation

Department of Biochemistry and Molecular Pharmacology; Program in Bioinformatics and Integrative Biology; Program in Molecular Medicine

Date

11-18-2011

Document Type

Article

Medical Subject Headings

Animals; Argonaute Proteins; Cell Nucleus; Computational Biology; DNA Damage; DNA Transposable Elements; Drosophila Proteins; Drosophila melanogaster; Female; Fertility; *Gene Silencing; *Genome, Insect; Membrane Transport Proteins; Mutation; Oocytes; Ovary; Peptide Initiation Factors; Protein Structure, Tertiary; RNA Cleavage; RNA, Small Interfering; RNA-Induced Silencing Complex; Signal Transduction; Ubiquitin-Protein Ligases

Abstract

piRNAs guide PIWI proteins to silence transposons in animal germ cells. Reciprocal cycles of piRNA-directed RNA cleavage--catalyzed by the PIWI proteins Aubergine (Aub) and Argonaute3 (Ago3) in Drosophila melanogaster--expand the population of antisense piRNAs in response to transposon expression, a process called the Ping-Pong cycle. Heterotypic Ping-Pong between Aub and Ago3 ensures that antisense piRNAs predominate. We show that qin, a piRNA pathway gene whose protein product contains both E3 ligase and Tudor domains, colocalizes with Aub and Ago3 in nuage, a perinuclear structure implicated in transposon silencing. In qin mutants, less Ago3 binds Aub, futile Aub:Aub homotypic Ping-Pong prevails, antisense piRNAs decrease, many families of mobile genetic elements are reactivated, and DNA damage accumulates in nurse cells and oocytes. We propose that Qin enforces heterotypic Ping-Pong between Aub and Ago3, ensuring that transposons are silenced and maintaining the integrity of the germline genome.

Rights and Permissions

Citation: Mol Cell. 2011 Nov 18;44(4):572-84. doi: 10.1016/j.molcel.2011.10.011. Link to article on publisher's site

Comments

Author Zhao Zhang is a student in the Interdisciplinary Graduate Program in the Graduate School of Biomedical Sciences (GSBS) at UMass Medical School.

Related Resources

Link to Article in PubMed

Keywords

UMCCTS funding

PubMed ID

22099305