School of Public Health, Wuhan University of Science and Technology, Wuhan, China.
Andrology. 2013 May;1(3):431-9. doi: 10.1111/j.2047-2927.2013.00069.x. Epub 2013 Feb 27.
Spermiogenesis is the final phase of spermatogenesis. During this process, haploid round spermatids differentiate into spermatozoa, with dramatic morphological changes, including elongation and condensation of the nuclei, and formation of the flagella. Meig1 is one of many genes involved in the regulation of this process. Male mice deficient in MEIG1 are sterile with a severe defect in spermiogenesis, associated with dramatic disruption of the spermatid manchette and failure of flagellogenesis. A yeast two-hybrid screen using full-length MEIG1 as bait identified transcription factor-like 5 protein (TCFL5) as a putative interacting proteins. Interestingly, this protein was also identified as a potential binding partner of SPAG16, another protein essential for spermatogenesis, and also a binding partner of MEIG1. The interaction between TCFL5 and MEIG1 was confirmed in cultured cells over-expressing the two proteins. The mouse Tcfl5 transcript is present only in the testis, and its expression is significantly increased during spermiogenesis. However, little is known about TCFL5 protein and its role in male germ cells. A rabbit polyclonal antibody was generated against the C-terminal region of TCFL5. Mouse TCFL5 protein was expressed in the testis but not in mature spermatozoa. During the first wave of spermatogenesis, TCFL5 expression was dramatically increased at day 30 after birth. In the testis and a mixture of dispersed testicular cells, the protein co-localized with α-tubulin, a manchette marker in early elongating spermatids. The protein also localized in the centrioles of late elongating spermatids. No obvious differences in TCFL5 epitope abundance and localization were observed between wild type and the Meig1-deficient mice. These findings suggest that TCFL5 may play a role upstream of MEIG1 action, and based on putative binding partners and localization is likely to be involved in spermiogenesis and formation of the sperm flagella.
精子发生是精子发生的最后阶段。在此过程中，单倍体圆形精母细胞分化为精子，形态发生剧烈变化，包括核的伸长和浓缩，以及鞭毛的形成。Meig1 是参与此过程调节的众多基因之一。缺乏 MEIG1 的雄性小鼠不育，精子发生严重缺陷，与精母细胞鞘的剧烈破坏和鞭毛发生失败有关。使用全长 MEIG1 作为诱饵的酵母双杂交筛选鉴定了转录因子样 5 蛋白 (TCFL5) 作为潜在的相互作用蛋白。有趣的是，该蛋白还被鉴定为另一种对精子发生至关重要的蛋白质 SPAG16 的潜在结合伴侣，也是 MEIG1 的结合伴侣。在过表达两种蛋白质的培养细胞中证实了 TCFL5 和 MEIG1 之间的相互作用。鼠 Tcfl5 转录本仅存在于睾丸中，其表达在精子发生过程中显著增加。然而，关于 TCFL5 蛋白及其在雄性生殖细胞中的作用知之甚少。针对 TCFL5 的 C 末端区域生成了兔多克隆抗体。在睾丸中表达了小鼠 TCFL5 蛋白，但在成熟精子中没有表达。在第一次精子发生过程中，出生后第 30 天 TCFL5 表达急剧增加。在睾丸和分散的睾丸细胞混合物中，该蛋白与α-微管蛋白共定位，α-微管蛋白是早期伸长的精母细胞中的鞘标记物。该蛋白还定位于晚期伸长的精母细胞的中心粒中。在野生型和 Meig1 缺陷型小鼠之间，TCFL5 表位丰度和定位没有明显差异。这些发现表明 TCFL5 可能在 MEIG1 作用的上游发挥作用，并且基于假定的结合伴侣和定位，可能参与精子发生和精子鞭毛的形成。
