Delcuve G P, Davie J R
Nucleic Acids Res. 1987 Apr 24;15(8):3385-96. doi: 10.1093/nar/15.8.3385.
The chromatin structure of a germ-line specific gene, the TPG-3 gene, one of the rainbow trout protamine genes was analyzed in various tissues. The protamine genes are expressed in early stage testis but not in late stage testis, liver or erythrocyte. Five potential CpG methylation sites in the coding and flanking regions of the TPG-3 protamine gene were monitored in early and late stage testis, nucleoprotamine, liver and erythrocyte. In all cases the patterns of methylation were identical with only one CpG site at position -740 being methylated. Thus, the methylation pattern of this protamine gene remained the same independently of the expression of the gene. Two Msp I sites at positions -293 and/or -275 and +155 were accessible to the enzyme in the TPG-3 chromatin of early stage testis. Since the Msp I site at position -293 and/or -275 was also present in the TPG-3 chromatin of liver, only the site at position +155 within the transcribed region correlated with the expression of the protamine gene.
在不同组织中分析了生殖系特异性基因——虹鳟鱼精蛋白基因之一TPG - 3基因的染色质结构。精蛋白基因在睾丸早期表达，但在睾丸晚期、肝脏或红细胞中不表达。在睾丸早期和晚期、核精蛋白、肝脏和红细胞中监测了TPG - 3精蛋白基因编码区和侧翼区的五个潜在CpG甲基化位点。在所有情况下，甲基化模式都是相同的，只有位于-740位置的一个CpG位点发生甲基化。因此，该精蛋白基因的甲基化模式与基因表达无关，保持不变。在睾丸早期的TPG - 3染色质中，位于-293和/或-275以及+155位置的两个Msp I位点可被该酶作用。由于位于-293和/或-275位置的Msp I位点在肝脏的TPG - 3染色质中也存在，所以只有转录区内位于+155位置的位点与精蛋白基因的表达相关。
