A pathway of gene-controlled events inS.cerevisiae cell cycleStart28MFCS24iDS821CKHUBETR11419DS26913IND716172015mND2314NMBE=budemergence,NM-nuclearmigration,CK=cytokinesis,CS=cell separation,iDS=initiation ofDNA synthesisDS=DNAsynthesis,mND=medial nucleardivision,IND-latenucleardivision,MF=matingfactor,19-16
Copyright © The McGraw-Hill Companies, Inc. Permission required to reproduce or display 19-16 A pathway of gene-controlled events in S. cerevisiae cell cycle BE=bud emergence, NM=nuclear migration, CK=cytokinesis, CS=cell separation, iDS=initiation of DNA synthesis DS=DNA synthesis, mND=medial nuclear division, lND=late nuclear division, MF=mating factor
Some important cell-cycle andDNA repairgenesTABLE19.1Some Important Cell-CycleandDNA Repair GenesGenesGeneProductsandTheirFunctionCDKSEnzymesknownascyclin-dependentproteinkinasesthatcontroltheactivityofotherproteinsbyphosphorylatingthemCDC28ACDkdiscovered intheyeastSaccharomycescerevisiaethatcontrolsseveral stepsintheS.cerevisiaecell cycleCDC2ACDkdiscoveredintheyeastSchizosaccharomycespombethatcontrolsseveralstepsintheS.pombecell cycle;alsothedesignationforaparticularCDKinmammaliancellsCDK4ACDKofmammaliancellsimportantfortheG,-to-StransitionCDK2ACDKofmammaliancellsimportantfortheG,-to-StransitioncyclinsProteinsthatarenecessaryforandinfluencetheactivityofCDKscyclinDAcyclinofmammaliancellsimportantfortheG,-to-StransitioncyclinEAcyclinofmammaliancellsimportantfortheG,-to-StransitioncyclinAAcyclinofmammaliancellsimportantforSphasecyclinBAcyclinofmammaliancellsimportantfortheG-to-MtransitionE2FAtranscriptionfactorofmammaliancellsimportantfortheG,-to-StransitionRBAmammalianproteinthatinhibitsE2Fp21AproteinofmammaliancellsthatinhibitsCDKactivityP16AproteinofmammaliancellsthatinhibitsCDKactivityP53AtranscriptionfactorofmammaliancellsthatactivatestranscriptionofDNArepairgenesaswellastranscriptionofp21RAD9Aproteinthat inhibits theGz-to-Mtransitionof S.cerevisiae inresponseto DNAdamageE6AproteinoftheHPVvirusthatinhibitsp53E7AproteinoftheHPVvirusthatinhibitsRb19-17
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Cyclin-dependentkinases(CDK)control thecellcyclebyphosphorylating substrateproteinsCDKCDK-cyclincomplex(a)CyclinPhosphorylationInactivationActivationActiveInactiveInactiveActiveFig.19.1319-18
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Nuclear laminsUnderlieinner surface of the nuclear membraneProbablyprovide structural supportfornucleusMay also be site for assembly ofDNA replication,transcription,RNAtransport,and chromosome structureproteinsDissolution of nuclear membrane during mitosis is triggered by CDKphosphorylation of nuclear lamins.Nuclearenvelope(b)NuclearlaminSpindlePhosphorylation券oflamins.LaminsbecomesolubleCDKNucleuswithintactDissolutionofnuclearCyclinnuclearmembranemembrane19-19Fig.19.13
Copyright © The McGraw-Hill Companies, Inc. Permission required to reproduce or display 19-19 Nuclear Nuclear lamins Underlie inner surface of the nuclear membrane Underlie inner surface of the nuclear membrane Probably provide structural support for nucleus Probably provide structural support for nucleus May also be site for assembly May also be site for assembly of DNA replication, transcription, of DNA replication, transcription, RNA transport, and chromosome structure proteins transport, and chromosome structure proteins Dissolution of nuclear membrane during mitosis is triggered by C Dissolution of nuclear membrane during mitosis is triggered by CDK phosphorylation phosphorylation of nuclear of nuclear lamins. Fig. 19.13
Human CDKs and cyclins can function in yeastinplaceofnativeproteinsYeastcellswithHumantemperature-sensitiveCDNACDKgeneSSYeastCENvectorTransformwithhumanPlateat36°CcDNAlibraryinyeastCENvector.Plateat36°CNocoloniesIsolatesCENvector(onlytransformedcontaininghumanCDKgenecoloniescangrowCENvectorcontaininghumanCDKgene19-20
Copyright © The McGraw-Hill Companies, Inc. Permission required to reproduce or display 19-20 Human CDKs and cyclins cyclins can function in yeast can function in yeast in place of native proteins in place of native proteins