Rb/Cdk2/Cdk4 triple mutant mice elicit an alternative mechanism for regulation of the G1/S transition

Forskningsoutput: TidskriftsbidragArtikel i vetenskaplig tidskrift

Abstract

The G1/S-phase transition is a well-toned switch in the mammalian cell cycle. Cdk2, Cdk4, and the rate-limiting tumor suppressor retinoblastoma protein (Rb) have been studied in separate animal models, but interactions between the kinases and Rb in vivo have yet to be investigated. To further dissect the regulation of the G1 to S-phase progression, we generated Cdk2-/-Cdk4-/-Rb-/- (TKO) mutant mice. TKO mice died at midgestation with major defects in the circulatory systems and displayed combined phenotypes of Rb-/- and Cdk2 -/-Cdk4-/- mutants. However, TKO mouse embryonic fibroblasts were not only resistant to senescence and became immortal but displayed enhanced S-phase entry and proliferation rates similar to wild type. These effects were more remarkable in hypoxic compared with normoxic conditions. Interestingly, depletion of the pocket proteins by HPV-E7 or p107/p130 shRNA in the absence of Cdk2/Cdk4 elicited a mechanism for the G1/S regulation with increased levels of p27Kip1 binding to Cdk1/cyclin E complexes. Our work indicates that the G1/S transition can be controlled in different ways depending on the situation, resembling a regulatory network.

Detaljer

Författare
Externa organisationer
  • National Cancer Institute at Frederick
  • University of Wisconsin-Madison
  • Institute of Molecular and Cell Biology
  • Oncodesign
Forskningsområden

Nyckelord

Originalspråkengelska
Sidor (från-till)486-491
Antal sidor6
TidskriftProceedings of the National Academy of Sciences of the United States of America
Volym106
Utgivningsnummer2
StatusPublished - 2009 jan 13
PublikationskategoriForskning
Peer review utfördJa
Externt publiceradJa