Linked Life Data

9094096

Source:http://linkedlifedata.com/resource/pubmed/id/9094096

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
4
pubmed:dateCreated
1997-6-10
pubmed:abstractText
Topoisomerases are nuclear enzymes that remove torsional stress in DNA. Their function is important for replication, transcription, chromosome condensation, and chromosome segregation during mitosis and meiosis. The goal of this work is to analyze both expression and function of topoisomerases during the meiotic stages of mammalian spermatogenesis. The patterns of expression of topoisomerase I and topoisomerase II alpha genes were followed on Northern blots of RNA from testes of mice of different ages and from specific germ cell populations. The transcript of the topoisomerase I gene was highest in somatic cells of the testis and in the mitotically proliferating spermatogonia and meiotic prophase spermatocytes, with the level of transcript decreasing dramatically in postmeiotic spermatids. In contrast, the levels of topoisomerase II alpha transcript were negligible in germ-cell free testes and highest in late meiotic prophase cells and round spermatids. Enzyme activity for both topoisomerase I and topoisomerase II was detected in both pachytene spermatocytes and in round spermatids; topoisomerase II exhibited a higher level of activity in meiotic spermatocytes than in round spermatids. In cultured cells, camptothecin, an inhibitor of topoisomerase I, caused some abnormalities of paired meiotic homologs, but did not inhibit the transition to metaphase. In contrast, teniposide and ICRF-193, inhibitors of topoisomerase II, dramatically inhibited the formation of metaphase chromosomes in cells induced to progress from prophase to metaphase. However, the disassembly of the synaptonemal complex was not inhibited, indicating that this process could be uncoupled from condensation of chromatin to form chromosomes. These studies constitute evidence for a functional requirement for topoisomerase II activity in the transition from meiotic prophase to meiotic metaphase I in mammalian spermatocytes.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Apr
pubmed:issn
1040-452X
pubmed:author
pubmed:issnType
Print
pubmed:volume
46
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
489-98
pubmed:dateRevised
2010-11-18
pubmed:meshHeading
pubmed-meshheading:9094096-Animals, pubmed-meshheading:9094096-Cells, Cultured, pubmed-meshheading:9094096-DNA Topoisomerases, Type I, pubmed-meshheading:9094096-DNA Topoisomerases, Type II, pubmed-meshheading:9094096-Enzyme Inhibitors, pubmed-meshheading:9094096-Gene Expression Regulation, Developmental, pubmed-meshheading:9094096-Gene Expression Regulation, Enzymologic, pubmed-meshheading:9094096-Male, pubmed-meshheading:9094096-Meiosis, pubmed-meshheading:9094096-Metaphase, pubmed-meshheading:9094096-Mice, pubmed-meshheading:9094096-Mice, Inbred ICR, pubmed-meshheading:9094096-Okadaic Acid, pubmed-meshheading:9094096-Prophase, pubmed-meshheading:9094096-Protein Kinases, pubmed-meshheading:9094096-Spermatozoa, pubmed-meshheading:9094096-Teniposide, pubmed-meshheading:9094096-Topoisomerase I Inhibitors, pubmed-meshheading:9094096-Topoisomerase II Inhibitors
pubmed:year
1997
pubmed:articleTitle
Analysis of expression and function of topoisomerase I and II during meiosis in male mice.
pubmed:affiliation
Dept. Biochemistry and Cellular and Molecular Biology, University of Tennessee, Knoxville 37996-0840, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S.