MAD1 and p27(KIP1) cooperate to promote terminal differentiation of granulocytes and to inhibit Myc expression and cyclin E-CDK2 activity.
To understand how cellular differentiation is coupled to withdrawal from the cell cycle, we have focused on two negative regulators of the cell cycle, the MYC antagonist MAD1 and the cyclin-dependent kinase inhibitor p27(KIP1). Generation of Mad1/p27(KIP1) double-null mice revealed a number of synthetic effects between the null alleles of Mad1 and p27(KIP1), including embryonic lethality, increased proliferation, and impaired differentiation of granulocyte precursors. Furthermore, with granulocyte cell lines derived from the Mad1/p27(KIP1) double-null mice, we observed constitutive Myc expression and cyclin E-CDK2 kinase activity as well as impaired differentiation following treatment with an inducer of differentiation. By contrast, similar treatment of granulocytes from Mad1 or p27(KIP1) single-null mice resulted in differentiation accompanied by downregulation of both Myc expression and cyclin E-CDK2 kinase activity. In the double-null granulocytic cells, addition of a CDK2 inhibitor in the presence of differentiation inducer was sufficient to restore differentiation and reduce Myc levels. We conclude that Mad1 and p27(KIP1) operate, at least in part, by distinct mechanisms to downregulate CDK2 activity and Myc expression in order to promote cell cycle exit during differentiation.
McArthur
Grant A
GA
Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, Washington 98109-1024, USA.
Foley
Kevin P
KP
Fero
Matthew L
ML
Walkley
Carl R
CR
Deans
Andrew J
AJ
Roberts
James M
JM
Eisenman
Robert N
RN
D000818:Animals; D042846:CDC2-CDC28 Kinases; D002453:Cell Cycle / Q000187:drug effects; D018797:Cell Cycle Proteins / Q000378:metabolism*; D002454:Cell Differentiation; D002460:Cell Line; D019927:Cyclin E / Q000037:antagonists & inhibitors* / Q000378:metabolism; D051357:Cyclin-Dependent Kinase 2; D050760:Cyclin-Dependent Kinase Inhibitor p27; D018844:Cyclin-Dependent Kinases / Q000037:antagonists & inhibitors* / Q000378:metabolism; D005231:Fatty Acids, Unsaturated / Q000494:pharmacology; D005260:Female; D005434:Flow Cytometry; D015972:Gene Expression Regulation, Neoplastic; D016259:Genes, myc / Q000235:genetics*; D006098:Granulocytes / Q000166:cytology* / Q000378:metabolism; D006412:Hematopoietic Stem Cells / Q000378:metabolism; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D009687:Nuclear Proteins; D010750:Phosphoproteins / Q000378:metabolism*; D017346:Protein Serine-Threonine Kinases / Q000037:antagonists & inhibitors* / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D012097:Repressor Proteins / Q000378:metabolism*; D016160:Retinoblastoma Protein / Q000378:metabolism; D013764:Tetrahydronaphthalenes / Q000494:pharmacology; D013997:Time Factors; D025521:Tumor Suppressor Proteins / Q000378:metabolism*
C430898:AGN 194204; C493961:Cdkn1b protein, mouse; D018797:Cell Cycle Proteins; D019927:Cyclin E; D005231:Fatty Acids, Unsaturated; C501385:Mad1l1 protein, mouse; D009687:Nuclear Proteins; D010750:Phosphoproteins; D012333:RNA, Messenger; D012097:Repressor Proteins; D016160:Retinoblastoma Protein; D013764:Tetrahydronaphthalenes; D025521:Tumor Suppressor Proteins; D050760:Cyclin-Dependent Kinase Inhibitor p27; D017346:Protein Serine-Threonine Kinases; D042846:CDC2-CDC28 Kinases; C495893:Cdk2 protein, mouse; D051357:Cyclin-Dependent Kinase 2; D018844:Cyclin-Dependent Kinases