Yeast IME2 functions early in meiosis upstream of cell cycle-regulated SBF and MBF targets.

In Saccharomyces cerevisiae, the G1 cyclin/cyclin-dependent kinase (CDK) complexes Cln1,-2,-3/Cdk1 promote S phase entry during the mitotic cell cycle but do not function during meiosis. It has been proposed that the meiosis-specific protein kinase Ime2, which is required for normal timing of pre-me...

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Main Authors: George S Brush, Nicole A Najor, Alan A Dombkowski, Daniela Cukovic, Kara E Sawarynski
Format: Article
Language:English
Published: Public Library of Science (PLoS) 2012-01-01
Series:PLoS ONE
Online Access:http://europepmc.org/articles/PMC3290606?pdf=render
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author George S Brush
Nicole A Najor
Alan A Dombkowski
Daniela Cukovic
Kara E Sawarynski
author_facet George S Brush
Nicole A Najor
Alan A Dombkowski
Daniela Cukovic
Kara E Sawarynski
author_sort George S Brush
collection DOAJ
description In Saccharomyces cerevisiae, the G1 cyclin/cyclin-dependent kinase (CDK) complexes Cln1,-2,-3/Cdk1 promote S phase entry during the mitotic cell cycle but do not function during meiosis. It has been proposed that the meiosis-specific protein kinase Ime2, which is required for normal timing of pre-meiotic DNA replication, is equivalent to Cln1,-2/Cdk1. These two CDK complexes directly catalyze phosphorylation of the B-type cyclin/CDK inhibitor Sic1 during the cell cycle to enable its destruction. As a result, Clb5,-6/Cdk1 become activated and facilitate initiation of DNA replication. While Ime2 is required for Sic1 destruction during meiosis, evidence now suggests that Ime2 does not directly catalyze Sic1 phosphorylation to target it for destabilization as Cln1,-2/Cdk1 do during the cell cycle.We demonstrated that Sic1 is eventually degraded in meiotic cells lacking the IME2 gene (ime2Δ), supporting an indirect role of Ime2 in Sic1 destruction. We further examined global RNA expression comparing wild type and ime2Δ cells. Analysis of these expression data has provided evidence that Ime2 is required early in meiosis for normal transcription of many genes that are also periodically expressed during late G1 of the cell cycle.Our results place Ime2 at a position in the early meiotic pathway that lies upstream of the position occupied by Cln1,-2/Cdk1 in the analogous cell cycle pathway. Thus, Ime2 may functionally resemble Cln3/Cdk1 in promoting S phase entry, or it could play a role even further upstream in the corresponding meiotic cascade.
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spelling doaj.art-8f30eba503e341bfb6a9892e66eace1a2022-12-21T18:32:44ZengPublic Library of Science (PLoS)PLoS ONE1932-62032012-01-0172e3157510.1371/journal.pone.0031575Yeast IME2 functions early in meiosis upstream of cell cycle-regulated SBF and MBF targets.George S BrushNicole A NajorAlan A DombkowskiDaniela CukovicKara E SawarynskiIn Saccharomyces cerevisiae, the G1 cyclin/cyclin-dependent kinase (CDK) complexes Cln1,-2,-3/Cdk1 promote S phase entry during the mitotic cell cycle but do not function during meiosis. It has been proposed that the meiosis-specific protein kinase Ime2, which is required for normal timing of pre-meiotic DNA replication, is equivalent to Cln1,-2/Cdk1. These two CDK complexes directly catalyze phosphorylation of the B-type cyclin/CDK inhibitor Sic1 during the cell cycle to enable its destruction. As a result, Clb5,-6/Cdk1 become activated and facilitate initiation of DNA replication. While Ime2 is required for Sic1 destruction during meiosis, evidence now suggests that Ime2 does not directly catalyze Sic1 phosphorylation to target it for destabilization as Cln1,-2/Cdk1 do during the cell cycle.We demonstrated that Sic1 is eventually degraded in meiotic cells lacking the IME2 gene (ime2Δ), supporting an indirect role of Ime2 in Sic1 destruction. We further examined global RNA expression comparing wild type and ime2Δ cells. Analysis of these expression data has provided evidence that Ime2 is required early in meiosis for normal transcription of many genes that are also periodically expressed during late G1 of the cell cycle.Our results place Ime2 at a position in the early meiotic pathway that lies upstream of the position occupied by Cln1,-2/Cdk1 in the analogous cell cycle pathway. Thus, Ime2 may functionally resemble Cln3/Cdk1 in promoting S phase entry, or it could play a role even further upstream in the corresponding meiotic cascade.http://europepmc.org/articles/PMC3290606?pdf=render
spellingShingle George S Brush
Nicole A Najor
Alan A Dombkowski
Daniela Cukovic
Kara E Sawarynski
Yeast IME2 functions early in meiosis upstream of cell cycle-regulated SBF and MBF targets.
PLoS ONE
title Yeast IME2 functions early in meiosis upstream of cell cycle-regulated SBF and MBF targets.
title_full Yeast IME2 functions early in meiosis upstream of cell cycle-regulated SBF and MBF targets.
title_fullStr Yeast IME2 functions early in meiosis upstream of cell cycle-regulated SBF and MBF targets.
title_full_unstemmed Yeast IME2 functions early in meiosis upstream of cell cycle-regulated SBF and MBF targets.
title_short Yeast IME2 functions early in meiosis upstream of cell cycle-regulated SBF and MBF targets.
title_sort yeast ime2 functions early in meiosis upstream of cell cycle regulated sbf and mbf targets
url http://europepmc.org/articles/PMC3290606?pdf=render
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