Welch J E, Schatte E C, O'Brien D A, Eddy E M
Gamete Biology Section, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, North Carolina 27709.
Biol Reprod. 1992 May;46(5):869-78. doi: 10.1095/biolreprod46.5.869.
A cDNA clone encoding a putative glyceraldehyde 3-phosphate dehydrogenase (GAPD-S) protein specific to spermatogenic cells was isolated from a mouse spermatogenic cell expression library. The Gapd-s cDNA contained 1451 bp of transcribed sequence, including an ATG initiation codon and a poly(A) addition signal. The location of the Gapd-s initiation codon differed from that of other Gapd sequences, resulting in a germ cell GAPD-S protein predicted to contain 105 additional residues at the amino terminus. While GAPD is constitutively expressed in somatic tissues, Northern blot analysis demonstrated that a Gapd-s probe hybridized to a 1.5-kb transcript present only in the testis. The Gapd-s mRNA was first detected during postnatal development in the testes of 20-day-old mice, suggesting that gene expression begins shortly after the appearance of haploid round spermatids. Northern analysis of RNA from isolated mouse pachytene spermatocytes and spermatids confirmed that Gapd-s expression is confined to post-meiotic germ cells. GAPD has been previously proposed to be the key enzyme regulating glycolysis in isolated round spermatids. We hypothesize that the GAPD-S enzyme plays an important role in regulating the switch between different pathways for energy production during spermiogenesis and in the spermatozoon.
从一个小鼠生精细胞表达文库中分离出一个编码假定的生精细胞特异性甘油醛-3-磷酸脱氢酶（GAPD-S）蛋白的cDNA克隆。Gapd-s cDNA包含1451 bp的转录序列，包括一个ATG起始密码子和一个聚腺苷酸（poly(A)）添加信号。Gapd-s起始密码子的位置与其他Gapd序列不同，导致预测的生殖细胞GAPD-S蛋白在氨基末端含有105个额外的残基。虽然GAPD在体细胞组织中组成性表达，但Northern印迹分析表明，Gapd-s探针与仅存在于睾丸中的1.5 kb转录本杂交。Gapd-s mRNA在出生后发育过程中首次在20日龄小鼠的睾丸中检测到，这表明基因表达在单倍体圆形精子细胞出现后不久开始。对分离的小鼠粗线期精母细胞和精子细胞的RNA进行Northern分析证实，Gapd-s表达仅限于减数分裂后的生殖细胞。先前有人提出GAPD是调节分离的圆形精子细胞中糖酵解的关键酶。我们假设GAPD-S酶在精子发生过程中以及精子中调节不同能量产生途径之间的转换中起重要作用。
