C. elegans piRNAs mediate the genome-wide surveillance of germline transcripts.
Cell
; 150(1): 78-87, 2012 Jul 06.
Article
en En
| MEDLINE
| ID: mdl-22738724
ABSTRACT
Piwi Argonautes and Piwi-interacting RNAs (piRNAs) mediate genome defense by targeting transposons. However, many piRNA species lack obvious sequence complementarity to transposons or other loci; only one C. elegans transposon is a known piRNA target. Here, we show that, in mutants lacking the Piwi Argonaute PRG-1 (and consequently its associated piRNAs/21U-RNAs), many silent loci in the germline exhibit increased levels of mRNA expression with a concomitant depletion of RNA-dependent RNA polymerase (RdRP)-derived secondary small RNAs termed 22G-RNAs. Sequences depleted of 22G-RNAs are proximal to potential target sites that base pair imperfectly but extensively to 21U-RNAs. We show that PRG-1 is required to initiate, but not to maintain, silencing of transgenes engineered to contain complementarity to endogenous 21U-RNAs. Our findings support a model in which C. elegans piRNAs utilize their enormous repertoire of targeting capacity to scan the germline transcriptome for foreign sequences, while endogenous germline-expressed genes are actively protected from piRNA-induced silencing.
Texto completo:
1
Colección:
01-internacional
Banco de datos:
MEDLINE
Asunto principal:
Caenorhabditis elegans
/
ARN de Helminto
/
ARN Interferente Pequeño
/
Genoma de los Helmintos
Tipo de estudio:
Prognostic_studies
/
Screening_studies
Límite:
Animals
Idioma:
En
Revista:
Cell
Año:
2012
Tipo del documento:
Article
País de afiliación:
Estados Unidos