Caenorhabditis elegans homologue of the human azoospermia factor DAZ is required for oogenesis but not for spermatogenesis

DAZ (Deleted in Azoospermia), the putative azoospermia factor gene in human , encodes a ribonucleoprotein-type RNA-binding protein required for spermat ogenesis, A Drosophila homologue of DAZ, called bottle, is also essential f or spermatogenesis. A mouse homologue, Dazla, is implicated in both spermat ogenesis and oogenesis, Here, we report the identification and characteriza tion of daz-1, the single DAZ homologue in the nematode Caenorhabditis eleg ans, Loss of daz-1 function caused sterility in hermaphrodites, by blocking oogenesis at the pachytene stage of meiosis I, Epistasis analysis suggeste d that this gene executes its function succeeding gld-1, which governs the early pachytene stage in the oogenic pathway. Spermatogenesis did not appea r to be affected in daz-1 hermaphrodites. Males defective in daz-1 produced sperm fully competent in fertilization, Analysis employing sex-determinati on mutants indicated that the daz-1 function was required for meiosis of fe male germline regardless of the sea of the soma, Transcription of daz-1 was restricted to the germline, starting Drier to the onset of meiosis and was most conspicuous in cells undergoing oogenesis, Thus, daz-1 in C, elegans is an essential factor for female meiosis but, unlike other DAZ family memb ers so far reported, it is dispensable for male meiosis.