Selective passage through the uterotubal junction of sperm from a mixed population produced by chimeras of calmegin-knockout and wild-type male mice
Selective passage through the uterotubal junction of sperm from a mixed population produced by chimeras of calmegin-knockout and wild-type male mice
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DOI：
10.1095/biolreprod.104.028647
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发表时间：
2004-09-01
影响因子：
3.6
通讯作者：
Okabe, M
中科院分区：
文献类型：
--
作者：
Nakanishi, T;Isotani, A;Okabe, M
Calmegin是一种睾丸特有的内质网伴侣蛋白，它的缺失会导致男性不育，因为精子在进入输卵管时表现出缺陷，不会与透明带结合。为了阐明缺陷迁移的机制，将野生型胚胎与缺乏功能calmegin基因的转基因小鼠的胚胎聚合，并在其顶体中表达增强型绿色荧光蛋白(EGFP)，从而获得了XY XY嵌合体。嵌合精液中含有野生型、非荧光精子，以及带有EGFP标记的顶体和有缺陷的calmegin基因的精子。转基因、野生型和嵌合型雄性与野生型雌性交配；然而，在输卵管中只发现了野生型精子。Calmegin基因敲除的精子，即使它们与野生型精子以嵌合射精的形式结合在一起，也仍然留在子宫输卵管交界处之外。这些发现表明，野生型精子的存在不能弥补冷冻敲除精子进入输卵管的能力，成功进入输卵管取决于单个精子的能力。
Loss of calmegin, a testis-specific putative chaperone protein of the endoplasmic reticulum, leads to male sterility because the sperm show defects in migration into the oviduct and do not bind to the zona pellucida. To clarify the mechanism of defective migration, XY XY chimeras were produced by aggregating wild-type embryos with embryos of transgenic mice lacking functional calmegin genes and expressing enhanced green fluorescent protein (EGFP) in their acrosomes. Chimeric ejaculates contained wild-type, nonfluorescent sperm as well as sperm with EGFP-tagged acrosomes and the defective calmegin gene. Transgenic, wild-type, and chimeric males were mated to wildtype females; however, only wild-type sperm were ever found within the oviducts. Calmegin-knockout sperm, even when they were combined in chimeric ejaculates with wild-type sperm, remained outside of the uterotubal junction. These findings indicate that the presence of wild-type sperm cannot compensate for the inability of calmegin-knockout sperm to enter the oviduct and that successful ascent into the oviduct depends on the capabilities of individual sperm.