Regulation of the proliferating cell nuclear antigen cyclin and thymidine kinase mRNA levels by growth factors.

摘要: The enzymes of the DNA synthesizing machinery constitute a group gene products that are generally expressed co-ordinately at G1/S boundary cell cycle. We have investigated how growth factors regulate steady-state mRNA levels two these genes, PCNA (proliferating nuclear antigen)/cyclin and thymidine kinase genes. To detect PCNA/cyclin mRNA, we isolated cDNA clone from human library. Two different lines were used for studies: BALB/c3T3 cells, which exquisitely sensitive to factors, ts13 temperature-sensitive (ts) mutant cycle, arrests in G1 restrictive temperature. RNAs genes under conditions also compared with histone H3 RNA good indicators fraction cells S phase. Both share fundamental characteristics, i.e. they not inducible G1-specific ts cycle temperature their expression is inhibited by cycloheximide, indicating unlike early growth-regulated require previous other However, show differences, most notable being epidermal factor alone, while not.