Four DAZ genes in two clusters found in the AZFc region of the human Y chromosome
Four DAZ genes in two clusters found in the AZFc region of the human Y chromosome
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DOI：
10.1006/geno.2000.6260
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发表时间：
2000-08-01
期刊：
影响因子：
4.4
通讯作者：
Page, DC
中科院分区：
文献类型：
--
作者：
Saxena, R;de Vries, JWA;Page, DC
DAZ基因是位于人类Y染色体AZFc区域内的候选生育因子，其缺失是生精失败的常见原因。DAZ基因的数量一直难以确定，部分原因是DAZ基因的核苷酸序列几乎相同。在这里，荧光原位杂交和BAC克隆的表征揭示了人类Y染色体上的四个全长DAZ基因。它们存在于两个簇中，每个簇包含一对反向DAZ基因（3'3'）。基因组序列和睾丸转录物的分析表明，三个或四个DAZ基因被翻译。每个基因含有至少7个串联拷贝的先前描述的，2.4 kb的重复单位，编码24个氨基酸。此外，两个DAZ基因含有一个10.8 kb重复单位的串联拷贝，该重复单位编码RNA结合结构域，该结构域在一些DAZ蛋白中似乎是多聚化的。结合我们目前的研究结果与以前的研究，我们可以重建几个步骤的DAZ基因在Y染色体上的进化。在祖先Y染色体DAZ基因中，两个基因内重复序列的扩增在人类和食蟹猴（旧大陆）谱系分化之前就开始了。在随后的进化过程中，发生了这种修饰基因的反向复制。最后，复制产生的两个基因簇，产生在现代人类Y染色体上发现的两簇/四基因排列。(C)北京大学出版社.
The DAZ genes are candidate fertility factors that lie within the human Y chromosome's AZFc region, whose deletion is a common cause of spermatogenic failure. The number of DAZ genes has been difficult to determine, in part because the nucleotide sequences of the DAZ genes are nearly identical. Here, fluorescence in situ hybridization and characterization of BAC clones revealed four full-length DAZ genes on the human Y chromosome. They exist in two clusters, each comprising an inverted pair of DAZ genes (3' 3'), Analysis of genomic sequences and testicular transcripts suggested that three or four DAZ genes are translated. Each gene contains at least seven tandem copies of a previously described, 2.4-kb repeat unit that encodes 24 amino acids. In addition, two DAZ genes contain tandem copies of a 10.8-kb repeat unit that encodes the RNA-binding domain, which appears to be multimerized in some DAZ proteins. Combining our present results with previous studies, we can reconstruct several steps in the evolution of the DAZ genes on the Y chromosome. In the ancestral Y-chromosomal DAZ gene, amplification of both intragenic repeats began before the human and cynomolgus (Old World) monkey lineages diverged. During subsequent evolution, an inverted duplication of this modified gene occurred. Finally, the resulting two-gene cluster was duplicated, generating the two-cluster/four-gene arrangement found on modern human Y chromosomes. (C) 2000 Academic Press.