Active digestion of sperm mitochondrial DNA in single living sperm revealed by optical tweezers
Active digestion of sperm mitochondrial DNA in single living sperm revealed by optical tweezers
复制标题
DOI：
10.1073/pnas.0506911103
复制
发表时间：
2006-01-31
影响因子：
11.1
通讯作者：
Kuroiwa, T
中科院分区：
文献类型：
--
作者：
Nishimura, Y;Yoshinari, T;Kuroiwa, T
在几乎所有真核生物中，线粒体（mt）基因主要从母本传递给后代。对于这种现象最流行的解释是父本线粒体DNA的简单稀释，因为父本配子（精子）比母本配子（卵子）小得多，并且为后代贡献了有限数量的线粒体。最近，这一简单的解释在一些报告中受到了挑战，这些报告描述了精子 mtDNA 的主动消化、精子中 mtDNA 复制的下调以及泛素化引发的线粒体蛋白水解。在这项研究中，我们通过使用高度敏感的 SYBR green I 活体染色来可视化活精子中的 mt 核仁。可视化 mt 核的能力使我们能够澄清，受精时精子 mtDNA 的消除是通过两个步骤实现的：(i) 在精子发生过程中 mt 核的数量逐渐减少，(ii) 受精后精子 mtDNA 的快速消化。值得注意的一点是，线粒体 DNA 的消化是在线粒体结构完全破坏之前完成的，这对于避免潜在有害的精子线粒体 DNA 扩散和传播给后代可能是必要的。
In almost all eukaryotes, mitochondrial (mt) genes are transmitted to progeny mainly from the maternal parent. The most popular explanation for this phenomenon is simple dilution of paternal mtDNA, because the paternal gametes (sperm) are much smaller than maternal gametes (egg) and contribute a limited amount of mitochondria to the progeny. Recently, this simple explanation has been challenged in several reports that describe the active digestion of sperm mtDNA, down-regulation of mtDNA replication in sperm, and proteolysis of mitochondria triggered by ubiquitination. In this investigation, we visualized mt nucleoids in living sperm by using highly sensitive SYBR green I vital staining. The ability to visualize mt nucleoids allowed us to clarify that the elimination of sperm mtDNA upon fertilization is achieved through two steps: (i) gradual decrease of mt nucleoid numbers during spermatogenesis and (ii) rapid digestion of sperm mtDNA just after fertilization. One notable point is that the digestion of mtDNA is achieved before the complete destruction of mitochondrial structures, which may be necessary to avoid the diffusion and transmission of potentially deleterious sperm mtDNA to the progeny.