Klemm U, Lee C H, Burfeind P, Hake S, Engel W
Institute of Human Genetics, University of Göttingen.
Biol Chem Hoppe Seyler. 1989 Apr;370(4):293-301. doi: 10.1515/bchm3.1989.370.1.293.
The nucleotide sequence of a 342-base cDNA encoding the rat protamine has been determined. This insert, isolated from a rat testis cDNA library, encodes a polypeptide of 50 amino acids of which 29 are arginine 9 are cysteine and 2 are tyrosine. The insert contains the complete 3'-noncoding region of 170 bases and 18 bases of the 5'-noncoding region. Hybridization of the protamine cDNA with the RNA prepared from testes of prepubertal and sexually mature rats revealed that protamine mRNA is first detectable as a 600 nucleotide long molecule in the 35-day old testis containing around 15% of round spermatids but not in testis of younger animals. The RNA of 50-day old and sexually mature rats was found to contain a second protamine mRNA which is around 500 nucleotides in length. Hybridization of the protamine cDNA with the RNA of isolated spermatids of the mature testis resulted in 2 prominent hybridization signals (600 and 500 bp) while the faint signal obtained with the RNA of pachytene spermatocytes (600 bp) was found to be due to contamination of the cell preparation by spermatids. After digestion of the mRNAs with ribonuclease H a single hybridization band even smaller than 500 nucleotides was obtained. As demonstrated on testis sections the transcripts are confined to the central layers of the tubuli seminiferi corresponding to the spatial arrangement of corresponding to the spatial arrangement of postmeiotic cells. The results indicate that the protamine gene in the rat is postmeiotically expressed and that the mRNA undergoes post-transcriptional processing that includes a reduction in molecular size with respect to the poly-(A)+ tail.
已确定编码大鼠鱼精蛋白的342个碱基的cDNA的核苷酸序列。该插入片段从大鼠睾丸cDNA文库中分离得到，编码一个由50个氨基酸组成的多肽，其中29个为精氨酸，9个为半胱氨酸，2个为酪氨酸。该插入片段包含170个碱基的完整3'-非编码区和18个碱基的5'-非编码区。鱼精蛋白cDNA与青春期前和性成熟大鼠睾丸制备的RNA杂交显示，鱼精蛋白mRNA首先在含有约15%圆形精子细胞的35日龄睾丸中作为一个600个核苷酸长的分子被检测到，而在较年轻动物的睾丸中未检测到。发现50日龄和性成熟大鼠的RNA含有第二种鱼精蛋白mRNA，其长度约为500个核苷酸。鱼精蛋白cDNA与成熟睾丸分离的精子细胞的RNA杂交产生2个明显的杂交信号（600和500 bp），而粗线期精母细胞的RNA（600 bp）获得的微弱信号被发现是由于精子细胞对细胞制备物的污染。用核糖核酸酶H消化mRNA后，获得了一个甚至小于500个核苷酸的单一杂交带。如在睾丸切片上所示，转录本局限于曲细精管对应于减数分裂后细胞空间排列的中央层。结果表明，大鼠中的鱼精蛋白基因在减数分裂后表达，并且mRNA经历转录后加工，包括相对于聚（A）+尾的分子大小减小。
