Subcellular localization of phospholipase Cζ in human sperm and its absence in DPY19L2-deficient sperm are consistent with its role in oocyte activation
Subcellular localization of phospholipase Cζ in human sperm and its absence in DPY19L2-deficient sperm are consistent with its role in oocyte activation
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DOI：
10.1093/molehr/gau098
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发表时间：
2015-02-01
影响因子：
4
通讯作者：
Arnoult, Christophe
中科院分区：
文献类型：
--
作者：
Escoffier, Jessica;Yassine, Sandra;Arnoult, Christophe
我们最近确认DPY19L2基因是人类球精症(70%)的主要遗传原因，并描述了DPY19L2基因敲除(KO)小鼠忠实地复制了人类球精症的表型，使其成为描述地球精子症分子生理学的极佳模型。最近对非遗传性球状精子症男性的案例研究表明，被认为在受精时诱导钙振荡的精子因子磷脂酶C，Zeta(PLC Zeta)在他们的精子中缺失，这解释了这些精子的受精潜力很低。由于30%的球精症男性仍未表现出遗传特征，DPY19L2球精症男性中缺乏PLC Zeta的说法仍有待正式证实。此外，PLC Zeta的精确定位及其在全球精子症患者精子发生过程中丢失的原因仍不清楚。在此，我们发现在患有DPY19L2相关球状精子症的人和小鼠精子中，PLC Zeta缺失或其存在高度减少。因此，用DPY19L2 KO小鼠的精子受精未能启动钙振荡，注射的卵母细胞仍然停留在中期II阶段，尽管少数人卵母细胞注射了DPY19L2缺陷的精子显示形成了2-原核胚胎。我们首次报道了PLC Zeta在控制人类精子中的亚细胞定位，该精子位于顶体内膜和核膜周围，位于与赤道区对应的区域。由于这些细胞成分在全球精子中不存在，因此PLC Zeta在全球精子中的缺失是一致的，并加强了PLC Zeta作为卵母细胞激活所必需的卵母细胞激活因子的作用。在我们的配套文章中，我们证明了Dpy1912 KO小鼠精子发生过程中的染色质紧致是有缺陷的，并导致精子DNA损伤。总而言之，这些缺陷解释了DPY19L2-全球精子症精子受精潜力较差，以及使用DPY19L2基因缺失患者的精子获得的胚胎发育潜力受损的原因。
We recently identified the DPY19L2 gene as the main genetic cause of human globozoospermia (70%) and described that Dpy19l2 knockout (KO) mice faithfully reproduce the human phenotype of globozoospermia making it an excellent model to characterize the molecular physiopathology of globozoospermia. Recent case studies on non-genetically characterized men with globozoospermia showed that phospholipase C, zeta (PLC zeta), the sperm factor thought to induce the Ca2+ oscillations at fertilization, was absent from their sperm, explaining the poor fertilization potential of these spermatozoa. Since 30% of globozoospermic men remain genetically uncharacterized, the absence of PLC zeta in DPY19L2 globozoospermic men remains to be formally established. Moreover, the precise localization of PLC zeta and the reasons underlying its loss during spermatogenesis in globozoospermic patients are still not understood. Herein, we show that PLC zeta is absent, or its presence highly reduced, in human and mouse sperm with DPY19L2-associated globozoospermia. As a consequence, fertilization with sperm from Dpy19l2 KO mice failed to initiate Ca2+ oscillations and injected oocytes remained arrested at the metaphase II stage, although a few human oocytes injected with DPY19L2-defective sperm showed formation of 2-pronuclei embryos. We report for the first time the subcellular localization of PLC zeta in control human sperm, which is along the inner acrosomal membrane and in the perinuclear theca, in the area corresponding to the equatorial region. Because these cellular components are absent in globozoospermic sperm, the loss of PLC zeta in globozoospermic sperm is thus consistent and reinforces the role of PLC zeta as an oocyte activation factor necessary for oocyte activation. In our companion article, we showed that chromatin compaction during spermiogenesis in Dpy19l2 KO mouse is defective and leads to sperm DNA damage. Together, these defects explain the poor fertilization potential of DPY19L2-globozoospermic sperm and the compromised developmental potential of embryos obtained using sperm from patients with a deletion of the DPY19L2 gene.