Isolation of a hamster cDNA homologous to the mouse and human cyclin kinase inhibitory protein p27Kip1

We report here the isolation, cloning and sequencing of a hamster cDNA homologous to the mouse cyclin kinase inhibitory protein p27Kip1. The full length hamster cDNA sequence (p30 Kip1)5 revealed 91% similarity with the previously reported mouse and human cDNAs and coded for a protein of 198 amino acids, results which were very similar to that observed for the mouse and human protein. Western blotting analysis performed using a polyclonal antibody against a mouse cyclin kinase inhibitory protein, p27Kip1, revealed the presence of a strongly reactive protein band at 30 kDa (as opposed to 27 kDa in mouse and human cells) in cell lysate prepared from rat and hamster cells. Although the size of the cyclin kinase inhibitory protein cDNa transcript is similar in mouse and hamster, it is likely that the differential mobility of the hamster p30Kip1 protein compared to the mouse and human p27Kip1 protein could be due to post-translational modifications.