Nuclear binding of cell cycle-related proteins: cyclin A versus proliferating cell nuclear antigen (PCNA).
We have investigated the cell cycle-dependent nuclear binding of cyclin A and of the proliferating cell nuclear antigen (PCNA) in asynchronously growing human fibroblasts. To this purpose, we have applied flow cytometry immunofluorescence, a powerful technique for elucidating the cell cycle phase during which the nuclear binding occurs. We have observed that, in striking contrast with the distribution of nuclear-bound PCNA which is restricted to S phase, the immunofluorescence signal of the nuclear-bound form of cyclin A is high in the G1 and G2 phases of the cell cycle. These results suggest the involvement of nuclear-bound cyclin A in the G1/S and G2/M phase transitions.
Stivala
L A
LA
Istituto di Patologia Generale C Golgi, Università di Pavia, Italy.
Scovassi
A I
AI
Bianchi
L
L
Prosperi
E
E
D015415:Biomarkers; D002453:Cell Cycle; D002467:Cell Nucleus / Q000378:metabolism*; D016213:Cyclins / Q000378:metabolism*; D005347:Fibroblasts / Q000166:cytology / Q000378:metabolism*; D006801:Humans; D018809:Proliferating Cell Nuclear Antigen / Q000378:metabolism*; D016196:S Phase
D015415:Biomarkers; D016213:Cyclins; D018809:Proliferating Cell Nuclear Antigen