A HAPLOID EXPRESSED GENE-CLUSTER EXISTS AS A SINGLE CHROMATIN DOMAIN IN HUMAN SPERM
A HAPLOID EXPRESSED GENE-CLUSTER EXISTS AS A SINGLE CHROMATIN DOMAIN IN HUMAN SPERM
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DOI：
10.1074/jbc.270.15.8755
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发表时间：
1995-04-14
影响因子：
4.8
通讯作者：
KRAWETZ, SA
中科院分区：
文献类型：
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作者：
CHOUDHARY, SK;WYKES, SM;KRAWETZ, SA
哺乳动物精子发生的标志是核-组蛋白-DNA复合物最初被过渡蛋白破坏，最终被鱼精蛋白取代。这些低分子量碱性核蛋白中的三种的基因作为PRM 1、PRM 2和TNP 2的单个线性阵列存在于人类染色体16p13.2上。为了开始解决其转录增强的机制，将包含这些基因的人类基因组的类似于40个酶的区域引入小鼠的生殖系中。荧光原位杂交和Southern分析表明，这段人类基因组整合到独立的染色体位点，同时保持其保真度。转录分析表明，表达的内源性小鼠鱼精蛋白Prm 1和Prm 2基因，以及小鼠过渡蛋白Tnp 2基因表达沿着与他们的人转基因对应。这些转基因人类基因在该多基因簇内的表达模式忠实地代表了在体内观察到的。此外，该转基因基因簇的所有成员的表达比例与人睾丸中的相似。转基因构建体的拷贝数依赖性和位置非依赖性表达表明，相应的生物学位点包含在人类基因组的该区段内。此外，DNA酶I敏感性确定，在精子中，人PRM 1-> PRM 2-> TNP 2基因结构域被包含为类似于28.5-丝氨酸蛋白酶的连续片段，其由一系列核基质相关拓扑异构酶II共有位点界定。这是第一次描述的多基因雄性配子特异性结构域作为一个基本的基因调控单位。提出了一个单倍体特异性基因决定模型。
Mammalian spermiogenesis is marked by the initial disruption of the nuclear-histone-DNA complex by the transition proteins for ultimate replacement with protamines. The genes for three of these low molecular weight basic nuclear proteins exist as a single linear array of PRM1, PRM2, and TNP2 on human chromosome 16p13.2. To begin to address the mechanism governing their transcriptional potentiation, a region of similar to 40 kilobases of the human genome encompassing these genes was introduced into the germ line of mice. Fluorescence in situ hybridization and Southern analysis showed that this segment of the human genome integrated into independent chromosomal sites while maintaining its fidelity. Transcript analysis demonstrated that the expression of the endogenous mouse protamine Prm1 and Prm2 genes as well as the mouse transition protein Tnp2 gene were expressed along with their human transgene counterparts. The pattern of expression of these transgenic human genes within this multigenic cluster faithfully represented that observed in vivo. In addition, all members of this transgenic gene cluster were expressed in proportions similar to those in human testis. Copy number-dependent and position-independent expression of the transgenic construct demonstrated that the corresponding biological locus was contained within this segment of the human genome. Furthermore, DNase I sensitivity established that in sperm the human PRM1-->PRM2-->TNP2 genic domain was contained as an similar to 28.5-kilobase contiguous segment bounded by an array of nuclear matrix associated topoisomerase II consensus sites. This is the first description of a multigenic male gamete-specific domain as a fundamental gene regulatory unit. A model of haploid-specific gene determination is presented.