Centriole replication. A study of spermatogenesis in the snail Viviparus.
Centriole replication. A study of spermatogenesis in the snail Viviparus.
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DOI：
10.1083/jcb.10.2.163
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发表时间：
1961-06
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影响因子：
--
通讯作者：
GALL, J G
中科院分区：
文献类型：
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作者：
GALL, J G
本文描述了在精子发生过程中的中心粒复制的前鳃蜗牛，胎生锤螺Reeve。从OsO4固定的睾丸片上切下电镜切片，包埋在聚酯树脂Vestopal W中。存在两种精母细胞。这导致了典型的单鞭毛精子携带9条染色体的单倍体，而非典型的多鞭毛精子只有一条染色体。在最年轻的典型精母细胞中有两个中心粒。每个都是直径约160 mµ、长约330 mµ的空心圆柱体。细胞壁由9组三重纤维组成，排列成一种特有的模式。在粗线期之前的某个时候，一个未成熟的中心粒，或称原中心粒，出现在每个成熟中心粒的旁边。原中心粒除了长度外，在大多数方面类似于成熟的中心粒：它更像是环形而不是管状。子原中心点的轴垂直于其亲本的轴。据推测，它在前期晚期生长到完整的大小，尽管成熟阶段还没有用电子显微镜观察到。这表明，中心粒具有恒定极化。远端形成鞭毛或其他中心粒产物，而近端代表原中心粒并与复制有关。前期的四个中心粒（两个亲本和两个子代）通过两次减数分裂分布到四个典型的精子细胞中，它们在精子细胞中起鞭毛基体的作用。非典型精母细胞首先含有两个正常的中心粒。每一个都被一簇原中心粒包围，在后期前期逐渐伸长。两次异常减数分裂后，中心粒簇形成多鞭毛精子的基体。根据Pollister首先提出的理论，即非典型细胞中的多余中心粒来源于退化染色体的着丝粒，对这些事实进行了讨论。
This paper describes the replication of centrioles during spermatogenesis in the Prosobranch snail, Viviparus malleatus Reeve. Sections for electron microscopy were cut from pieces of testis fixed in OsO4 and embedded in the polyester resin Vestopal W. Two kinds of spermatocytes are present. These give rise to typical uniflagellate sperm carrying the haploid number of 9 chromosomes, and atypical multiflagellate sperm with only one chromosome. Two centrioles are present in the youngest typical spermatocyte. Each is a hollow cylinder about 160 mµ in diameter and 330 mµ long. The wall consists of 9 sets of triplet fibers arranged in a characteristic pattern. Sometime before pachytene an immature centriole, or procentriole as it will be called, appears next to each of the mature centrioles. The procentriole resembles a mature centriole in most respects except length: it is more annular than tubular. The daughter procentriole lies with its axis perpendicular to that of its parent. It presumably grows to full size during the late prophase, although the maturation stages have not been observed with the electron microscope. It is suggested that centrioles possess a constant polarization. The distal end forms the flagellum or other centriole products, while the proximal end represents the procentriole and is concerned with replication. The four centrioles of prophase (two parents and two daughters) are distributed by the two meiotic divisions to the four typical spermatids, in which they function as the basal bodies of the flagella. Atypical spermatocytes at first contain two normal centrioles. Each of these becomes surrounded by a cluster of procentrioles, which progressively elongate during the late prophase. After two aberrant meiotic divisions the centriole clusters give rise to the basal bodies of the multiflagellate sperm. These facts are discussed in the light of the theory, first proposed by Pollister, that the supernumerary centrioles in the atypical cells are derived from the centromeres of degenerating chromosomes.