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Formation of the redundant nuclear envelope in monkey spermatids

1968; Wiley; Volume: 161; Issue: 2 Linguagem: Inglês

10.1002/ar.1091610202

1097-0185

L. E. Franklin,

Animal Genetics and Reproduction

Abstract Development of redundant nuclear envelope was observed in Erythrocebus patas and Macaca mulatta spermatids. As the acrosome forms around the anterior part of the nucleus, the underlying nuclear envelope becomes more dense in appearance. Changes which lead ultimately to formation of the redundant nuclear envelope of mature spermatozoa involve only the posterior region of the envelope which does not lie beneath the acrosome. The first recognized change is separation of the nuclear envelope from underlying chromatin by an intervening band of lightly stained nuclear material, around the posterior quarter of the nucleus. The separation increases and the bulged region of the nuclear envelope is drawn caudally as nuclear condensation progresses. The caudally extended region of the nucleus is comprised of nuclear material of low electron density and pores are present in the envelope of the extended areas. The chromatin aggregates in late spermatids becomes homogeneous in appearance when the nucleus flattens into a paddle shape. Nuclear protrusions are present at both posterior corners of the flattened nucleus at this stage of spermiogenesis but only one protrusion is well developed. Membrane remnants of the extended nuclear envelope remain in mature spermatozoa as the redundant nuclear envelope.