Figure 2

The proteomic strategy used to identify sperm chromatin factors. Spermatogenic chromatin from him-8(e1489) males and oogenic chromatin from fer-1(hc1) hermaphrodites was purified. Proteins that co-purified with chromatin were examined by multidimensional protein identification technology (MudPIT). As a result, 1,099 spermatogenic proteins and 812 oogeneic proteins were identified. This list was then cut down to 502 high-abundance spermatogenic proteins. Of the abundant spermatogenic proteins, 132 were further selected after subtracting oogenic proteins. For functional analysis, RNAi against the genes that encode the spermatogenic proteins was carried out, and 50 genes showed embryonic lethal or sterile phenotypes. For germline phenotypic analysis, RNAi-treated worms were stained with DAPI: 20 genes that caused germline cytological defects when knocked down were identified; of these, 18 showed morphological defects in the male germline after RNAi.