Johann-Friedrich-Blumenbach-Institute of Zoology and Anthropology-Developmental Biology, GZMB, Ernst-Caspari-Haus, Justus-von-Liebig-Weg 11, Georg-August-Universität Göttingen, 37077 Göttingen, Germany.
Int J Mol Sci. 2022 Sep 7;23(18):10280. doi: 10.3390/ijms231810280.
ODF1 is a major protein of the accessory fibres of the mammalian sperm tail. In addition, ODF1 is found in the connecting piece, a complex structure located at the posterior end of the nucleus that connects the sperm head and tail. The tight coupling of the sperm head and tail is critical for the progressive motility of the sperm to reach the oocyte for fertilisation. The depletion of ODF1 by homologous recombination in mice led to male infertility. Although sperm tails were present in the epididymis, no intact spermatozoa were found. Instead, the depletion of ODF1 resulted in sperm decapitation, suggesting that ODF1 is essential for the formation of the coupling apparatus and the tight linkage of the sperm head and tail. However, the development of the linkage complex in the absence of ODF1 has never been investigated. Here, I analysed the fine structure of the developing connecting piece by transmission electron microscopy. I show that the connecting piece develops as in wild-type spermatids. Structural abnormalities were not observed when ODF1 was absent. Thus, ODF1 is dispensable for the development of the connecting piece. However, the decapitation of ODF1-deficient spermatozoa indicates that the heads and tails of the spermatozoa are not linked, so that they separate when force is applied.
ODF1 是哺乳动物精子尾部附属纤维的主要蛋白。此外，ODF1 还存在于连接段中，这是一种位于核后端的复杂结构，连接着精子的头部和尾部。精子头部和尾部的紧密连接对于精子的渐进运动至关重要，以便到达卵子进行受精。在小鼠中通过同源重组耗尽 ODF1 会导致雄性不育。尽管精子尾部存在于附睾中，但没有发现完整的精子。相反，ODF1 的耗尽导致精子断头，这表明 ODF1 对于形成连接装置和精子头部和尾部的紧密连接是必不可少的。然而，在缺乏 ODF1 的情况下，连接复合物的发育从未被研究过。在这里，我通过透射电子显微镜分析了正在发育的连接段的精细结构。我表明，连接段的发育与野生型精原细胞相似。当不存在 ODF1 时，没有观察到结构异常。因此，ODF1 对于连接段的发育不是必需的。然而，缺乏 ODF1 的精子断头表明精子的头部和尾部没有连接，因此当施加力时它们会分离。
