Absence of annulus in human asthenozoospermia: Case Report
Absence of annulus in human asthenozoospermia: Case Report
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DOI：
10.1093/humrep/dep020
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发表时间：
2009-06-01
影响因子：
6.1
通讯作者：
Toure, A.
中科院分区：
文献类型：
--
作者：
Lhuillier, P.;Rode, B.;Toure, A.
环带是位于精子鞭毛中段（MP）和主段（PP）交界处的基于隔蛋白的环状结构。在小鼠中，Septin 4（精子环的结构组分）的缺失阻止环形成并导致MP-PP分离、鞭毛弯曲、弱精子症和雄性不育。睾丸阴离子转运蛋白1（Tat 1）是SLC 26阴离子转运蛋白家族的生殖细胞特异性成员，与Septin 4在精子环共表达。有趣的是，Tat 1无效精子带有萎缩环，导致与Sept 4无效精子相似的表型。我们通过对精子涂片制备物进行免疫荧光检测，在弱精子症受试者（n = 75）和对照组的精子中寻找Tat 1错误表达和/或错误定位。我们发现1例患者表现为中度弱精子症，97%的精子在环处缺乏Tat 1、Septin 4和Septin 7蛋白。我们通过透射电子显微镜证实了环结构的缺失，并观察到患者的精子显示MP-PP分离和异常的线粒体组织。我们发现，精子中的结构缺陷不是由TAT 1和SEPT 4基因的异常转录或点突变引起的;然而，尽管这两种蛋白质都有表达，但它们并没有正确定位于精子环。我们研究的病例迄今为止尚未在人类中报道，证实了Tat 1和Septin蛋白参与了环的构成，但也提出了有关该结构在人类精子运动中的功能的问题。
The annulus is a septin-based ring structure located at the junction of the midpiece (MP) and the principal piece (PP) of spermatozoa flagellum. In the mouse, deletion of Septin 4, a structural component of the sperm annulus, prevents annulus formation and leads to MP-PP disjunction, flagellar bending, asthenozoospermia and male sterility. Testis anion transporter 1 (Tat1) is a germ cell-specific member of the SLC26 anion transporter family and is co-expressed with Septin 4 at the sperm annulus. Interestingly, Tat1 null sperm bear an atrophic annulus, causing a phenotype similar to that of Sept4 null sperm. We searched for Tat1 misexpression and/or mislocalization in spermatozoa from asthenozoospermic subjects (n = 75) and controls by performing an immunofluorescence detection assay on sperm smear preparations. We found one patient showing moderate asthenozoospermia, with 97% of sperm lacking Tat1, Septin 4 and Septin 7 proteins at the annulus. We confirmed the absence of the annulus structure by transmission electron microscopy and observed that spermatozoa from the patient displayed MP-PP disjunction and abnormal mitochondrial organization. We show that the structural defects in sperm are not caused by abnormal transcription or point mutations of the TAT1 and SEPT4 genes; however, although both proteins are expressed, they are not properly localized at sperm annulus. The case we studied, so far unreported in human, confirms the involvement of Tat1 and Septin proteins in the constitution of the annulus, but also raises questions about the function of this structure in human sperm motility.