Tsui S, Dai T, Roettger S, Schempp W, Salido E C, Yen P H
Department of Pediatrics, Harbor-UCLA Medical Center, Torrance, California 90509, USA.
Genomics. 2000 May 1;65(3):266-73. doi: 10.1006/geno.2000.6169.
The human DAZ (deleted in azoospermia) gene family on the Y chromosome and an autosomal DAZ-like gene, DAZL1, encode RNA-binding proteins that are expressed exclusively in germ cells. Their role in spermatogenesis is supported by their homology with a Drosophila male infertility gene boule and sterility of Daz11 knock-out mice. While all mammals contain a DAZL1 homologue on their autosomes, DAZ homologues are present only on the Y chromosomes of great apes and Old World monkeys. The DAZ and DAZL1 proteins differ in the copy numbers of a DAZ repeat and the C-terminal sequences. We studied the interaction of DAZ and DAZL1 with other proteins as an approach to investigate functional similarity between these two proteins. Using DAZ as bait in a yeast two-hybrid system, we isolated two DAZAP (DAZ-associated protein) genes. DAZAP1 encodes a novel RNA-binding protein that is expressed most abundantly in the testis, and DAZAP2 encodes a ubiquitously expressed protein with no recognizable functional motif. DAZAP1 and DAZAP2 bind similarly to both DAZ and DAZL1 through the DAZ repeats. The DAZAP genes were mapped to chromosomal regions 19p13.3 and 2q33-q34, respectively, where no genetic diseases affecting spermatogenesis are known to map.
Y染色体上的人类DAZ（无精子症缺失基因）基因家族以及一个常染色体上的类DAZ基因DAZL1，编码仅在生殖细胞中表达的RNA结合蛋白。它们与果蝇雄性不育基因boule的同源性以及Daz11基因敲除小鼠的不育现象，都支持了它们在精子发生过程中的作用。虽然所有哺乳动物在其常染色体上都含有一个DAZL1同源物，但DAZ同源物仅存在于大猩猩和旧世界猴的Y染色体上。DAZ和DAZL1蛋白在DAZ重复序列的拷贝数和C末端序列上有所不同。我们研究了DAZ和DAZL1与其他蛋白的相互作用，以此作为探究这两种蛋白功能相似性的一种方法。在酵母双杂交系统中以DAZ作为诱饵，我们分离出了两个DAZAP（DAZ相关蛋白）基因。DAZAP1编码一种新型RNA结合蛋白，在睾丸中表达最为丰富，而DAZAP2编码一种普遍表达的蛋白，没有可识别的功能基序。DAZAP1和DAZAP2通过DAZ重复序列与DAZ和DAZL1的结合方式相似。DAZAP基因分别定位于染色体区域19p13.3和2q33 - q34，目前已知没有影响精子发生的遗传疾病定位于这些区域。
