Dpy19l2-deficient globozoospermic sperm display altered genome packaging and DNA damage that compromises the initiation of embryo development.
Dpy19l2-deficient globozoospermic sperm display altered genome packaging and DNA damage that compromises the initiation of embryo development.
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DOI：
10.1093/molehr/gau099
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发表时间：
2015-02
影响因子：
4
通讯作者：
Sandra Yassine;J. Escoffier;G. Martinez;C. Coutton;Thomas Karaouzene;R. Zouari;J. Ravanat;C. Metzler-Guillemain;H. Lee;R. Fissore;S. Hennebicq;P. Ray;C. Arnoult
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文献类型：
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作者：
Sandra Yassine;J. Escoffier;G. Martinez;C. Coutton;Thomas Karaouzene;R. Zouari;J. Ravanat;C. Metzler-Guillemain;H. Lee;R. Fissore;S. Hennebicq;P. Ray;C. Arnoult
我们最近确定DPY 19 L2基因是人类球形精子症的主要遗传原因。非遗传特征的球形精子症病例与DNA改变相关，表明DPY 19 L2依赖性球形精子症可能与DNA质量差相关。然而，这种缺陷的起源还没有得到表征，对球形精子产生的胚胎质量的影响仍有待确定。使用缺乏Dpy 19 l2的小鼠模型，我们比较了核致密化的几个关键步骤。我们表明，组蛋白H4乙酰化波和过渡蛋白的出现和消失的动力学是有缺陷的。更重要的是，鱼精蛋白的核入侵不会发生。因此，我们发现球形精子表现为精子染色质致密化差和精子DNA完整性破坏。接下来，我们通过进行ICSI来评估使用这种缺陷精子的发育后果。我们在配套文章中指出，球形精子的卵母细胞激活（OA）非常差，并且由于缺乏磷脂酶C β;因此使用人工OA（AOA）绕过缺陷OA。在此，我们评估了小鼠ICSI + AOA产生的胚胎的发育潜力。我们证明，虽然OA是完全获救，植入前发育受损时，使用球形精子。在人类中，在没有AOA的情况下，DPY 19 L2缺失患者的精子可以产生少量胚胎，这些胚胎也显示出较差的发育潜力。综上所述，我们发现Dpy 19 l2基因敲除小鼠精子发生过程中染色质致密化是有缺陷的，并导致精子DNA损伤。当精子到达附睾时，大多数DNA断裂已经存在，这表明它们发生在睾丸内部。因此，这一结果表明，不建议在Dpy 19 l2依赖性球形精子症中进行睾丸精子提取。这些缺陷可能在很大程度上解释了大多数小鼠和人类胚胎发育不良的球形精子精子。
We recently identified the DPY19L2 gene as the main genetic cause of human globozoospermia. Non-genetically characterized cases of globozoospermia were associated with DNA alterations, suggesting that DPY19L2-dependent globozoospermia may be associated with poor DNA quality. However the origins of such defects have not yet been characterized and the consequences on the quality of embryos generated with globozoospermic sperm remain to be determined. Using the mouse model lacking Dpy19l2, we compared several key steps of nuclear compaction. We show that the kinetics of appearance and disappearance of the histone H4 acetylation waves and of transition proteins are defective. More importantly, the nuclear invasion by protamines does not occur. As a consequence, we showed that globozoospermic sperm presented with poor sperm chromatin compaction and sperm DNA integrity breakdown. We next assessed the developmental consequences of using such faulty sperm by performing ICSI. We showed in the companion article that oocyte activation (OA) with globozoospermic sperm is very poor and due to the absence of phospholipase Cζ; therefore artificial OA (AOA) was used to bypass defective OA. Herein, we evaluated the developmental potential of embryos generated by ICSI + AOA in mice. We demonstrate that although OA was fully rescued, preimplantation development was impaired when using globozoospermic sperm. In human, a small number of embryos could be generated with sperm from DPY19L2-deleted patients in the absence of AOA and these embryos also showed a poor developmental potential. In conclusion, we show that chromatin compaction during spermiogenesis in Dpy19l2 KO mouse is defective and leads to sperm DNA damage. Most of the DNA breaks were already present when the sperm reached the epididymis, indicating that they occurred inside the testis. This result thus suggests that testicular sperm extraction in Dpy19l2-dependent globozoospermia is not recommended. These defects may largely explain the poor embryonic development of most mouse and human embryos obtained with globozoospermic sperm.