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Activation of Both Mos and Cdc25 Is Required for G2-M Transition in Perch Oocyte

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Title Activation of Both Mos and Cdc25 Is Required for G2-M
Transition in Perch Oocyte
 
Creator Priyadarshini, Anamilka
Basu, Dipanjan
Navneet, A K
Bhattacharyya, Anirban
Bhattacharya, Shelley
Maitra, Sudipta
Bhattacharya, Samir
 
Subject Cell Biology & Physiology
 
Description Resumption of meiosis from diplotene arrest during the first meiotic prophase in
vertebrate oocytes is universally controlled by MPF, a heterodimer of Cdk1 and cyclin
B. Activation of MPF depends on the withdrawal of Cdk1 inhibition by Wee1/Myt1
kinase on the one hand and the activation of Cdk1 by Cdc25 phosphatase on the other.
It is relevant to know whether both these pathways are necessary to rescue diplotene
arrest or if either one of them is sufficient. In MIH (17a, 20b dihydroxy-4-pregnen-3-
one) incubated perch (Anabas testudineus) oocytes we have examined these
possibilities. Perch oocyte extract following MIH incubation showed a significant
increase in Myt1 phosphorylation from 12 to 16 hr indicating its progressive
deactivation. MIH induced Mos expression markedly increased at 16 hr effecting 95%
GVBD. Cycloheximide inhibited MIH induced Mos expression and its
phosphorylation, which in turn reduced Myt1 phosphorylation and GVBD. Myt1
phosphorylation was blocked in Mos immunodepleted oocytes. All these suggest the
involvement of Mos in Myt1 phosphorylation. Oocytes incubated in MIH for 16 hr
activated Cdc25, but such activation could not rescue the inhibition of GVBD due to
Myt1 in Mos immunodepleted oocytes. Blocking Cdc25 with an antisense oligo
significantly inhibited GVBD even though Myt1 remained deactivated during this
period. Taken together, our findings indicate that MIH requires both pathways for
perch oocyte maturation: the expression and activation of Mos, which is linked to Myt1
deactivation on the one hand, and the activation of Cdc25 on the other, as blocking
either pathway compromised G2-M transition in perch oocytes.
 
Publisher John Wiley & Sons
 
Date 2009
 
Type Article
PeerReviewed
 
Format application/pdf
 
Identifier http://www.eprints.iicb.res.in/248/1/MOLECULAR_REPRODUCTION_AND_DEVELOPMENT%2C76(3)%2C_289%2D300%2C_2009_[89].pdf
Priyadarshini, Anamilka and Basu, Dipanjan and Navneet, A K and Bhattacharyya, Anirban and Bhattacharya, Shelley and Maitra, Sudipta and Bhattacharya, Samir (2009) Activation of Both Mos and Cdc25 Is Required for G2-M Transition in Perch Oocyte. Molecular Reproduction and Development, 76 (3). pp. 289-300. ISSN 1040-452X
 
Relation http://dx.doi.org/10.1002/mrd.20952
http://www.eprints.iicb.res.in/248/