Overexpression of mouse D-type cyclins accelerates G1 phase in rodent fibroblasts.
Mammalian D-type cyclins are growth factor-regulated, delayed early response genes that are presumed to control progression through the G1 phase of the cell cycle by governing the activity of cyclin-dependent kinases (cdks). Overexpression of mouse cyclin D1 in serum-stimulated mouse NIH-3T3 and rat-2 fibroblasts increased their rates of G0 to S- and G1- to S-phase transit by several hours, leading to an equivalent contraction of their mean cell generation times. Although such cells remained contact inhibited and anchorage dependent, they manifested a reduced serum requirement for growth and were smaller in size than their normal counterparts. Ectopic expression of cyclin D2 in rodent fibroblasts, either alone or together with exogenous cdk4, shortened their G0- to S-phase interval and reduced their serum dependency, but cyclin D2 alone did not alter cell size significantly. When cells were microinjected during the G1 interval with a monoclonal antibody specifically reactive to cyclin D1, parental rodent fibroblasts and derivatives overexpressing this cyclin were inhibited from entering S phase, but cells injected near the G1/S phase transition were refractory to antibody-induced growth suppression. Thus, cyclin D1, and most likely D2, are rate limiting for G1 progression.
Quelle
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Department of Tumor Cell Biology, St. Jude Children's Research Hospital, Memphis, Tennessee 38105.
Ashmun
R A
RA
Shurtleff
S A
SA
Kato
J Y
JY
Bar-Sagi
D
D
Roussel
M F
MF
Sherr
C J
CJ
D016475:3T3 Cells; D000818:Animals; D048429:Cell Size; D019938:Cyclin D1; D056742:Cyclin D2; D051358:Cyclin-Dependent Kinase 4; D018844:Cyclin-Dependent Kinases; D016213:Cyclins / Q000096:biosynthesis / Q000235:genetics / Q000502:physiology*; D004261:DNA Replication; D005347:Fibroblasts / Q000187:drug effects / Q000378:metabolism; D016193:G1 Phase / Q000187:drug effects; D015870:Gene Expression; D051379:Mice; D015513:Oncogene Proteins / Q000096:biosynthesis / Q000235:genetics / Q000502:physiology*; D011494:Protein Kinases / Q000378:metabolism; D011518:Proto-Oncogene Proteins; D051381:Rats
C486196:Ccnd2 protein, mouse; C486197:Ccnd2 protein, rat; D056742:Cyclin D2; D016213:Cyclins; D015513:Oncogene Proteins; D011518:Proto-Oncogene Proteins; D019938:Cyclin D1; D011494:Protein Kinases; C495902:Cdk4 protein, mouse; C495903:Cdk4 protein, rat; D051358:Cyclin-Dependent Kinase 4; D018844:Cyclin-Dependent Kinases