Meichroacidin Containing the Membrane Occupation and Recognition Nexus Motif Is Essential for Spermatozoa Morphogenesis*
Meichroacidin Containing the Membrane Occupation and Recognition Nexus Motif Is Essential for Spermatozoa Morphogenesis*
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DOI：
10.1074/jbc.m708590200
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发表时间：
2008-07
影响因子：
4.8
通讯作者：
K. Tokuhiro;M. Hirose;Y. Miyagawa;A. Tsujimura;S. Irie;A. Isotani;M. Okabe;Y. Toyama;C. Ito;K. Toshimori;K. Takeda;S. Oshio;H. Tainaka;J. Tsuchida;A. Okuyama;Y. Nishimune;Hiromitsu Tanaka
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文献类型：
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作者：
K. Tokuhiro;M. Hirose;Y. Miyagawa;A. Tsujimura;S. Irie;A. Isotani;M. Okabe;Y. Toyama;C. Ito;K. Toshimori;K. Takeda;S. Oshio;H. Tainaka;J. Tsuchida;A. Okuyama;Y. Nishimune;Hiromitsu Tanaka
Meichroacidin（MCA）是一种高度亲水的蛋白质，其包含膜占据和识别连接基序。MCA在从粗线期精母细胞到成熟精子发育的精子发生阶段表达，并且定位于雄性减数分裂中期染色体和精子鞭毛中。MCA序列在玻璃海鞘、鲤鱼和哺乳动物中高度保守。为了研究MCA的生理作用，我们产生了MCA破坏的突变小鼠;纯合子MCA突变雄性不育，但雌性没有。MCA突变雄性的附睾头中很少观察到精子。然而，野生型和突变小鼠之间的睾丸质量几乎没有差异。在精子形态发生过程中，细长的精子细胞延缓了鞭毛的形成，并可能增加支持细胞的吞噬作用。免疫组织化学分析表明，MCA相互作用的蛋白质位于外部致密的纤维的鞭毛。MCA突变小鼠的睾丸精子经卵胞浆内单精子注射可成功受精卵，并产生健康的子代。我们的研究结果表明，MCA是必不可少的精子鞭毛的形成和功能精子的生产。
Meichroacidin (MCA) is a highly hydrophilic protein that contains the membrane occupation and recognition nexus motif. MCA is expressed during the stages of spermatogenesis from pachytene spermatocytes to mature sperm development and is localized in the male meiotic metaphase chromosome and sperm flagellum. MCA sequences are highly conserved in Ciona intestinalis, Cyprinus carpio, and mammals. To investigate the physiological role of MCA, we generated MCA-disrupted mutant mice; homozygous MCA mutant males were infertile, but females were not. Sperm was rarely observed in the caput epididymidis of MCA mutant males. However, little to no difference was seen in testis mass between wild-type and mutant mice. During sperm morphogenesis, elongated spermatids had retarded flagellum formation and might increase phagocytosis by Sertoli cells. Immunohistochemical analysis revealed that MCA interacts with proteins located on the outer dense fibers of the flagellum. The testicular sperm of MCA mutant mice was capable of fertilizing eggs successfully via intracytoplasmic sperm injection and generated healthy progeny. Our results suggest that MCA is essential for sperm flagellum formation and the production of functional sperm.