Zhang Y L, Akmal K M, Tsuruta J K, Shang Q, Hirose T, Jetten A M, Kim K H, O'Brien D A
State Key Laboratory of Molecular Biology, Shanghai Institute of Biochemistry, Chinese Academy of Sciences, China.
Mol Reprod Dev. 1998 May;50(1):93-102. doi: 10.1002/(SICI)1098-2795(199805)50:1<93::AID-MRD12>3.0.CO;2-Z.
Germ cell nuclear factor (GCNF/RTR), a novel orphan receptor in the nuclear receptor superfamily of ligand-activated transcription factors, is expressed predominantly in developing germ cells. In several mammalian species two GCNF/RTR mRNAs are present in the testis, with the smaller 2.3-kb transcript generally expressed at higher levels than the larger 7.4- or 8.0-kb transcript. In both the mouse and rat, the 2.3- and 7.4-kb GCNF/RTR transcripts were detected in isolated spermatogenic cells, but not in Sertoli cells. Expression of these transcripts is differentially regulated, with the larger 7.4-kb mRNA appearing earlier during testicular development. The major 2.3-kb transcript is expressed predominantly in round spermatids in the mouse and rat. In situ hybridization studies in the rat demonstrated that GCNF/RTR transcripts reach maximal steady-state levels in round spermatids at stages VII and VIII of the spermatogenic cycle, and then decline abruptly as spermatids begin to elongate. RNase protection assays were used to predict the 3' termination site of the 2.3-kb transcript. An alternative polyadenylation signal (AGUAAA) was identified just upstream of this termination site. These studies suggest that GCNF/RTR may regulate transcription during spermatogenesis, particularly in round spermatids just prior to the initiation of nuclear elongation and condensation.
生殖细胞核因子（GCNF/RTR）是配体激活转录因子核受体超家族中的一种新型孤儿受体，主要在发育中的生殖细胞中表达。在几种哺乳动物中，睾丸中存在两种GCNF/RTR mRNA，较小的2.3 kb转录本通常比较大的7.4 kb或8.0 kb转录本表达水平更高。在小鼠和大鼠中，在分离的生精细胞中检测到了2.3 kb和7.4 kb的GCNF/RTR转录本，但在支持细胞中未检测到。这些转录本的表达受到差异调节，较大的7.4 kb mRNA在睾丸发育过程中出现得更早。主要的2.3 kb转录本在小鼠和大鼠的圆形精子细胞中占主导地位。在大鼠中的原位杂交研究表明，GCNF/RTR转录本在生精周期的VII和VIII阶段在圆形精子细胞中达到最大稳态水平，然后随着精子细胞开始伸长而突然下降。核糖核酸酶保护试验用于预测2.3 kb转录本的3'末端位点。在该末端位点上游刚发现了一个替代的聚腺苷酸化信号（AGUAAA）。这些研究表明，GCNF/RTR可能在精子发生过程中调节转录，特别是在核伸长和浓缩开始之前的圆形精子细胞中。
