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Expression and localization of DNA topoisomerase II during rat spermatogenesis
Author(s) -
Chen JiLong,
Longo Frank J.
Publication year - 1996
Publication title -
molecular reproduction and development
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.745
H-Index - 105
eISSN - 1098-2795
pISSN - 1040-452X
DOI - 10.1002/(sici)1098-2795(199609)45:1<61::aid-mrd9>3.0.co;2-q
Subject(s) - biology , spermatogenesis , chromatin , nuclear matrix , microbiology and biotechnology , topoisomerase , spermatid , messenger rna , spermatocyte , dna , gene , genetics , endocrinology , meiosis
The potential role(s) of DNA topoiosmerase II (topo II) during chromatin changes that characterize different stages of spermatogenesis was investigated in the rat by an analysis of the expression and localization of topo II mRNA and protein in individual spermatogenic cells. Expression of topo II was restricted to spermatogonia, spermatocytes, and round and early‐elongating spermatids. Two protein bands of 177 and 170 kDa were detected in immunoblots of spermatocytes and round spermatids, while bands of 148 and 142 kDa were prominent in preparations of elongating spermatids. Topo II levels and distribution patterns, as observed by immunofluorescent microscopy, exhibited cell type‐specific variations. Differences in topo II staining patterns were also apparent when nuclear matrices of spermatogenic cells were prepared with different extraction conditions. In addition to its possible function as a structural component, topo II, associated with nuclear matrix preparations from spermatogenic cells, possessed catalytic activity. These observations indicate that both the 177 and 170 kDa and the 148 and 142 kDa forms of topo II share similar structural and functional properties. Topo IIβ mRNA was transcribed in rat spermatogenic cells at 6.2 kb. Relative levels of topo IIβ mRNA were high in spermatogonia and spermatocytes, and decreased in both round and early‐elongating spermatids. Changes in topo II expression levels and localization patterns represent distinct stage‐specific markers for the maturation of spermatogenic cells, and are consistent with the involvement of topo II in mediating DNA modifications and chromatin changes during spermatogenesis. © 1996 Wiley‐Liss, Inc.