摘要
Protamine is a kind small, basic protein rich in arginine residues and found to be complexed with DNA in spermatozoa. We have cloned a 150 bp cDNA encoding the rat protamine (rP) by RT PCR technique. Dig labelled cDNA for rP was used for Northern blot analysis to study the expression of P1 protamine gene in rat and mouse. P1 protamine mRNA was detected only in rat testis, no hybridization signals were detected in rat brain and lever. In addition, the presence of P1 protamine mRNA was detected not only in rat testis, but also in mouse testis. Dig labelled cDNA for mouse protamine 1 (mP1) was used to study the expression of mP1 gene during the process of sexual maturation of mouse. 7～8 d after birth, no mP1 mRNA could be detected. At d 24～26, mP1 mRNA was detectable migrating as a homogeneous band at 580 nucleotides, whereas in sexually mature animals, a heterogeneous mixture of RNAs ranging from 450～580 bases in length was observed. Histological studies revealed that in the testis of 7～8 day old mouse, spermatogenesis has developed to the spermatocyte stage, whereas round spermatids (Rs) were present in the testis of the mice with 24～26 d age and elongating spermatids (Es) were present in the testis of sexually mature animals. Electrophoresis of total nuclear basic proteins (TNBP) revealed that the Rs could possess the somatic histones, while Es was found to have protamine and less histone. These results indicate that the P1 protamine gene is tissues specifically expressed and the P1 protamine is showing to be conservative in evolution. During the process of sexual maturation, along with morphological changes, mP1 gene was transcribed in Rs and translated in Es. The mechanism of protamine gene expression was discussed.
Protamine is a kind small, basic protein rich in arginine residues and found to be complexed with DNA in spermatozoa. We have cloned a 150 bp cDNA encoding the rat protamine (rP) by RT PCR technique. Dig labelled cDNA for rP was used for Northern blot analysis to study the expression of P1 protamine gene in rat and mouse. P1 protamine mRNA was detected only in rat testis, no hybridization signals were detected in rat brain and lever. In addition, the presence of P1 protamine mRNA was detected not only in rat testis, but also in mouse testis. Dig labelled cDNA for mouse protamine 1 (mP1) was used to study the expression of mP1 gene during the process of sexual maturation of mouse. 7～8 d after birth, no mP1 mRNA could be detected. At d 24～26, mP1 mRNA was detectable migrating as a homogeneous band at 580 nucleotides, whereas in sexually mature animals, a heterogeneous mixture of RNAs ranging from 450～580 bases in length was observed. Histological studies revealed that in the testis of 7～8 day old mouse, spermatogenesis has developed to the spermatocyte stage, whereas round spermatids (Rs) were present in the testis of the mice with 24～26 d age and elongating spermatids (Es) were present in the testis of sexually mature animals. Electrophoresis of total nuclear basic proteins (TNBP) revealed that the Rs could possess the somatic histones, while Es was found to have protamine and less histone. These results indicate that the P1 protamine gene is tissues specifically expressed and the P1 protamine is showing to be conservative in evolution. During the process of sexual maturation, along with morphological changes, mP1 gene was transcribed in Rs and translated in Es. The mechanism of protamine gene expression was discussed.
基金
the National Pandeng Project! (970 2 110 19)
