Structure-function relationships in the sperm acrosome.
Structure-function relationships in the sperm acrosome.
复制标题
精子顶体的结构与功能关系。
DOI：
10.1111/j.1749-6632.1991.tb27313.x
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发表时间：
1991
影响因子：
5.2
通讯作者：
Winfrey,V
中科院分区：
文献类型：
--
作者：
Olson,GE;Winfrey,V
极化的哺乳动物精子由有限的细胞内细胞器组成，这些细胞器被隔离到特定的结构域。精子大小和形状的显著物种差异是由于这组共同的细胞器的大小和形状的差异，而不是由于它们的分布差异，这在物种之间是一致的。根据解剖学和生理学标准，精子的主要亚类是头部的顶体和顶体后区以及鞭毛的中段和主段区。这些领域的不同之处在于其组装的细胞器，在组成和结构的覆盖质膜和它们的功能在受精事件。'-6顶体段包括精子头部的前二分之一到三分之二，其功能是精卵结合、穿透卵子包埋物并最终与卵子质膜融合。向内看，这一节的主要成分包括质膜、下面的膜结合的顶体、一层电子致密的核周物质和最里面的浓缩核。顶体含有多种水解酶，这些水解酶被认为有助于精子穿透卵包埋物7，顶体由三个主要的亚部组成，称为顶段、主段和远端的赤道段。顶体的界膜由两个主要亚区组成：顶体外膜直接位于质膜之下，而顶体内膜面向核，并与核周电子致密物质并列。顶体内、外膜的亚结构域分别对应顶体的三个节段，具有不同的功能。在受精过程中，顶体顶段和主段的外顶体膜参与顶体反应的膜融合事件，与相邻的质膜一起形成有孔的杂交膜复合物，其允许释放顶体内容物。相反，顶体内膜成为顶体反应精子的质膜等价物;在某些物种中，该膜被认为在精子与透明膜的初级结合或维持精子-透明膜相互作用中起作用
The polarized mammalian spermatozoon is constructed from a limited set of intracellular organelles which are sequestered to specific domains. The striking species differences in the size and shape of spermatozoa results from differences in the size and shape of this common set of organelles and not from differences in their distribution, which is consistent between species. I Based on anatomical and physiological criteria the major subdivisions of the spermatozoon are the acrosomal and postacrosomal domains of the head and the midpiece and principal piece domains of the flagellum. These domains differ in their assemblage of organelles, in the composition and structure of the overlying plasma membrane and in their function in fertilization events.'-6 The acrosomal segment comprises the anterior one-half to two-thirds of the sperm head and it functions in sperm-egg binding, penetration of the egg investments, and ultimately fusion with the egg plasma membrane.'-6 Proceeding inward the major components of this segment include the plasma membrane, the underlying membranebounded acrosome, a layer of electron dense perinuclear material and, innermost, the condensed nucleus. The acrosome contains a variety of hydolases which are thought to facilitate sperm penetration of the egg investments7 and it is made up of three major subdivisions termed the apical segment, the principal segment, and, distally, the equatorial segment. The limiting membrane of the acrosome consists of two major subregions: the outer acrosomal membrane immediately underlies the plasma membrane while the inner acrosomal membrane faces the nucleus and is in apposition with the perinuclear electron dense material. The subdomains of the inner and outer acrosomal membranes corresponding to the three acrosomal segments exhibit different functions. During fertilization the outer acrosomal membrane of the apical and principal segments participates in the membrane fusion events of the acrosome reaction, forming in conjunction with the adjacent plasma membrane, a fenestrated hybrid membrane complex which permits release of the acrosomal contents. In contrast, the inner acrosomal membrane becomes the plasma membrane-equivalent of acrosome reacted spermatozoa; in some species, this membrane is believed to function in the primary binding of spermatozoa to the zona pellucida or in maintenance of sperm-zona interactions