Targeted disruption of intracellular type I platelet activating factor-acetylhydrolase catalytic subunits causes severe impairment in spermatogenesis
Targeted disruption of intracellular type I platelet activating factor-acetylhydrolase catalytic subunits causes severe impairment in spermatogenesis
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DOI：
10.1074/jbc.m211836200
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发表时间：
2003-04-04
影响因子：
4.8
通讯作者：
Arai, H
中科院分区：
文献类型：
--
作者：
Koizumi, H;Yamaguchi, N;Arai, H
I型血小板激活因子乙酰水解酶是一种磷脂酶，由两个同源催化亚基α1和α2以及I型无脑畸形致病基因的产物Lis1组成。在脑发育过程中，Lis1在神经元迁移中起着重要作用，但其催化亚基在体内的功能尚不清楚。在这项研究中，我们通过定向干扰产生了Alpha1和Alpha2缺陷小鼠。Alpha1(-/-)小鼠与野生型小鼠没有区别，而Alpha2(-/-)雄性小鼠的睾丸大小显著减小。双突变雄性小鼠由于严重的精子发生障碍而不育。组织学检查显示，精母细胞期生精细胞明显变性，生精小管内凋亡细胞增多。催化亚基在小鼠的睾丸和脑中都有高水平的表达。在野生型小鼠中，α2在所有类型的生精小管细胞中都有表达，而α1只在精原细胞中表达。这种表达模式与发现这两个亚基的缺失导致生殖细胞在早期生精阶段显著丧失的发现是平行的。我们还发现，在Alpha2(-/-)和双突变小鼠中，Lis1蛋白水平显著降低，但mRNA水平没有显著降低，这表明催化亚基，特别是Alpha2，是Lis1表达水平的决定因素。
Intracellular type I platelet activating factor-acetylhydrolase is a phospholipase that consists of a dimer of two homologous catalytic subunits alpha1 and alpha2 as well as LIS1, a product of the causative gene for type I lissencephaly. LIS1 plays an important role in neuronal migration during brain development, but the in vivo function of the catalytic subunits remains unclear. In this study, we generated alpha1- and alpha2-deficient mice by targeted disruption. alpha1(-/-) mice are indistinguishable from wild-type mice, whereas alpha2(-/-) male mice show a significant reduction in testis size. Double-mutant male mice are sterile because of severe impairment of spermatogenesis. Histological examination revealed marked degeneration at the spermatocyte stage and an increase of apoptotic cells in the seminiferous tubules. The catalytic subunits are expressed at high levels in testis as well as brain in mice. In wild-type mice, alpha2 is expressed in all seminiferous tubule cell types, whereas alpha1 is expressed only in the spermatogonia. This expression pattern parallels the finding that deletion of both subunits induces a marked loss of germ cells at an early spermatogenic stage. We also found that the LIS1 protein levels, but not the mRNA levels, were significantly reduced in alpha2(-/-) and double-mutant mice, suggesting that the catalytic subunits, especially alpha2, are a determinant of LIS1 expression level.