PgmNr W450: ELLI-1, a novel germline protein, modulates RNAi activity and P-granule accumulation in C. elegans.

Authors:
D. Updike; K. Andralojc; A. Campbell; A. Kelly; M. Terrey; P. Tanner; I. Gans; M. Senter-Zapata; E. Khokhar


Institutes
Mount Desert Island Biological Laboratory, Bar Harbor, ME.


Keyword: Germ line specification

Abstract:

                Germ cells contain non-membrane bound cytoplasmic organelles that help maintain germline integrity.  In C. elegans they are called P granules; without them, germ cells undergo partial masculinization or aberrant differentiation.  Many key P-granule components play roles in both exogenous and endogenous small RNA pathways.  CSR-1 represents a small-RNA binding P-granule protein that antagonizes the accumulation of sperm-specific transcripts in developing oocytes.  Loss of CSR-1 and its cofactors cause a very specific, enlarged P-granule phenotype.  To better understand the function of CSR-1 in P granules, PGL-1::GFP expressing worms were mutated and screened for enlarged P granules.  Ten mutants were isolated, including multiple alleles of csr-1 and its cofactors ego-1, ekl-1, and drh-3.  Two alleles are in a novel gene now called elli-1 (enlarged germline granules).  ELLI-1 becomes expressed in primordial germ cells during mid-embryogenesis and continues to be expressed in the adult germline.  ELLI-1 forms cytoplasmic aggregates that do not co-localize with P granules, but instead accumulate in the syncytial cytoplasm of the adult germline.  Genes encoding P-granule components, including those in the csr-1 pathway, are up-regulated in elli-1 mutants, as are several genes that promote RNAi.  This overexpression of RNAi genes is reflected in the enhanced RNAi phenotype of elli-1 worms.  Our results suggest that ELLI-1 is acting to modulate the accumulation of key transcripts required for exogenous and endogenous small RNA pathways.



Wormbase Genetic Index
1. pgl-1
2. csr-1
3. drh-3
4. ego-1
5. ekl-1
6. F20C5.3