Seligman J, Page D C
Department of Obstetrics/Gynecology, Rambam Medical Center, Haifa, Israel.
Biochem Biophys Res Commun. 1998 Apr 28;245(3):878-82. doi: 10.1006/bbrc.1998.8530.
The autosomal homologs of the human Y-chromosomal DAZ gene (DAZH and Dazh in human and mouse, respectively) are strong candidate for Azoospermia factor and encode a testis specific RNA-binding proteins. We studied the expression pattern of the mouse Dazh during embryonic development by using Northern-blotting of developing gonads. In the mouse, we have detected 3.5 kb and 4.5 kb transcripts in male and female embryonic gonads at 12.5 dpc (days post coitum). During this period, the only germ cells present in the gonad are primordial germ cells. Dazh transcripts were not detected in embryonic gonads of mice that lack germ cells because of mutation in W gene, suggesting that expression is limited to germ-cells. In females, oogonia enter meiosis at 13.5-14.5 dpc: at this time Dazh transcription levels are similar to those of the male (when prospermatogonia are in the male gonad). Transcription levels decrease steadily after birth as the number of oocytes is depleted and is hardly detectable by puberty. A human DAZH transcript was also detected by Northern-blotting in the human ovary in levels which are of about 100 fold lower than those observed in the human testis. The expression of the Dazh in male and female gonad before germ cell sex differentiation suggests that these genes may act at the first phase of male and female gametogenesis.
人类Y染色体DAZ基因的常染色体同源基因（分别在人类和小鼠中为DAZH和Dazh）是无精子症因子的有力候选基因，编码睾丸特异性RNA结合蛋白。我们通过对发育中的性腺进行Northern印迹分析，研究了小鼠Dazh在胚胎发育过程中的表达模式。在小鼠中，我们在妊娠12.5天（合子后天数）的雄性和雌性胚胎性腺中检测到了3.5 kb和4.5 kb的转录本。在此期间，性腺中存在的唯一生殖细胞是原始生殖细胞。在因W基因发生突变而缺乏生殖细胞的小鼠胚胎性腺中未检测到Dazh转录本，这表明其表达仅限于生殖细胞。在雌性中，卵原细胞在妊娠13.5 - 14.5天进入减数分裂：此时Dazh转录水平与雄性（当精原细胞在雄性性腺中时）相似。出生后，随着卵母细胞数量的减少，转录水平稳步下降，到青春期时几乎检测不到。通过Northern印迹分析还在人类卵巢中检测到了人类DAZH转录本，其水平比在人类睾丸中观察到的低约100倍。Dazh在生殖细胞性别分化之前在雄性和雌性性腺中的表达表明，这些基因可能在雄性和雌性配子发生的第一阶段起作用。
