PGL-1 is an RNA-binding protein component of germ granules and essential for fertility in Caenorhabditis elegans. To clarify the molecular function of PGL-1, we performed comparative proteomic analysis using 2-D DIGE and LC-MS/MS. Five groups of synchronized adult hermaphrodites were analyzed: (1) wild-type N2 grown at 20C, (2)
pgl-1(
bn101) mutants grown at 20C, (3)
pgl-1(
bn101) mutants grown at 20C then upshifted to 25C after the L1 stage, (4)
pgl-1(
ct131) mutants grown at 20C, and (5)
pgl-1(
ct131) mutants grown at 20C then upshifted to 25C after the L1 stage. The five groups were divided into two experimental sets for 2-D DIGE: set A included N2 and
pgl-1(
bn101) mutants, and set B included N2 and
pgl-1(
ct131) mutants. Dunnett's test indicated 90 and 100 specific spots, respectively, with significantly different expression levels from the rest of the experimental set (
q0.1). Among them, 69 and 58 spots, respectively, were analyzed by LC-MS/MS. Finally, we identified 19 proteins from 24 specific spots common to both the experimental sets. RNAi analysis indicated that decreased
eef-1G expression is strongly associated with the temperature-sensitive sterile phenotype of
pgl-1. Our results suggest that PGL-1 is closely involved in translational processes during C. elegans germline development.