Mutations in the C. elegans Piwi Argonaute orthologue prg-1
have previously been reported to result in reduced levels of thousands of germline-specific piRNAs as well as temperature-sensitive sterility (1, 2, 3). We find that outcrossing of prg-1
mutations results in homozygous strains with normal levels of fertility, but that propagation of these strains for 15 to 40 generations results in sterility. prg-1
mutants have previously been reported to display increased levels of Tc3 transposition. However, stereotypical germ cell development phenotypes occur at sterility, suggesting that progressive sterility is not induced by random Tc3-mediated mutations but rather by another form of heritable stress. Repression of daf-2
is well known to result in stress resistance and increased somatic lifespan in C. elegans (4). Independent daf-2
mutations were able to suppress the progressive sterility phenotype of prg-1
. Thus, reduced DAF-2-mediated insulin/IGF1 signaling can repress post-mitotic aging in somatic cells as well as proliferative aging in the germ line. These observations defy a prediction of the antagonistic pleiotropy theory of aging (5), which suggests that prolonged lifespan might result in compromised fertility.
1. Batista PJ, Ruby JG, Claycomb JM, Chiang R, Fahlgren N, Kasschau KD, Chaves DA, Gu W, Vasale JJ, Duan S, Conte Jr. D, Luo S, Schroth GP, Carrington JC, Bartel DP, Mello CC. Molecular Cell (2008)
2. Das PP, Bagijn MP, Goldstein LD, Woolford JR, Lehrbach NJ, Sapetschnig A, Buhecha HR, Gilchrist MJ, Howe KL, Stark R, Matthews N, Berezikov E, Ketting RF, Tavare S, Miska EA. Molecular Cell (2008)
3. Wang G, Reinke V. Current Biology (2008)
4. Kenyon C, Chang J, Gensch E, Rudner A. Nature (1993)
5. Willims GC. Evolution (1957).