Partitioning of the Golgi apparatus in rat primary and secondary spermatocytes during meiosis.
We examined the disassembly and reformation of the Golgi apparatus as a function of the cycle of the seminiferous epithelium in adult rats during stages XIII and XIV, i.e., just prior to and during meiosis I and II. Serial section analysis of primary spermatocytes at metaphase I demonstrated the presence of two Golgi complexes. At the ultrastructural level, these Golgi complexes were shown to be composed of stacks of cisternae and vesicles, with each stack having a varying number of saccules. Although Golgi complex intermediates resulting from the process of organelle disassembly were not clearly identified in diplotene spermatocytes immediately prior to nuclear envelope vesiculation, we did observe clusters of vesicles resembling the "nuage," with each cluster varying in size and number of vesicles. Meiosis I results in the formation of secondary spermatocytes that exhibit a well-formed spherical Golgi complex approximately half the size of the diplotene spermatocyte Golgi. Next, secondary spermatocytes enter meiosis II. In contrast to metaphase I, during metaphase II reformation of the Golgi apparatus into stacks was not observed and only small clusters of vesicles at two poles of dividing cells were detected. In addition, "nuage"-like structures were not identified during meiosis II. Our results begin to characterize the process by which Golgi apparatus partitioning is accomplished during meiosis, presumably resulting in the delivery of equal complements of this organelle to four round spermatids. We suggest that partitioning of the Golgi apparatus takes place prior to metaphase I and that the two steps of meiosis may exhibit subtle differences with respect to Golgi partitioning.
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Department of Anatomy and Cell Biology, Georgetown University Medical Center, Washington, D.C. 20007.
Suarez-Quian
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D000818:Animals; D006056:Golgi Apparatus / Q000648:ultrastructure*; D008297:Male; D008540:Meiosis; D008854:Microscopy, Electron; D051381:Rats; D011919:Rats, Inbred Strains; D013090:Spermatocytes / Q000648:ultrastructure*