Developmental changes in cyclin B1 and cyclin-dependent kinase 1 (CDK1) levels in the different populations of spermatogenic cells of the post-natal rat testis

Citation
M. Godet et al., Developmental changes in cyclin B1 and cyclin-dependent kinase 1 (CDK1) levels in the different populations of spermatogenic cells of the post-natal rat testis, EUR J CELL, 79(11), 2000, pp. 816-823
Citations number
32
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Cell & Developmental Biology
Journal title
EUROPEAN JOURNAL OF CELL BIOLOGY
ISSN journal
0171-9335 → ACNP
Volume
79
Issue
11
Year of publication
2000
Pages
816 - 823
Database
ISI
SICI code
0171-9335(200011)79:11<816:DCICBA>2.0.ZU;2-J
Abstract
Spermatogenesis is a highly ordered process which requires mitotic and meio tic divisions. In this work, we studied the relative changes in the levels of the two components of the M-phase promoting factor (MPF): the regulatory subunit cyclin BI (CycB1) and its catalytic submit cdk1, in spermatogenic cells of rats between 16 and 90 days of life. A multivariate flow cytometry analysis of forward scatter (FSC), side scatter (SSC) and DNA content was used to identify. six populations of rat germ cells: spermatogonia with pre leptotene spermatocytes, young pachytene spermatocytes, middle to late pach ytene spermatocytes, secondary spermatocytes with doublets of round spermat ids, round spermatids, and elongated spermatids, For any population studied no significant difference in the relative cellular content of CycB1 or cdk 1 proteins between animals of different ages was observed By contrast, CycB 1 and cdk1 levels were different between the different populations of germ cells. CycB1 and cdk1 were rather high in young pachytene spermatocytes and culminated in late spermatocytes, i.e. just before the first meiotic divis ion, The relative levels of the two proteins remained high in secondary spe rmatocytes then decreased in round spermatids at the exit of meiosis, Simil ar results were obtained by Western-blot analysis of total proteins obtaine d from lysates of elutriated fractions of spermatocytes and spermatids, MPF activity was assessed in lysates of germ cells from 32-day-old rats or adu lt animals using p13(sic1) agarose and histone H1 as an exogenous substrate . H1 kinase activity was higher in pachytene spermatocytes than in round sp ermatid fractions from both adult and young rats. These results indicate th at the meiotic G2/M transition is associated to high levels of CycB1 and cd k1 leading to high MPF activity irrespective of the age of the animals.