IDENTIFICATION OF P53 TARGET GENES THROUGH IMMUNE SELECTION OF GENOMIC DNA - THE CYCLIN-G GENE CONTAINS 2 DISTINCT P53 BINDING-SITES

An immune-selection procedure was employed in order to isolate p53-bin ding sites from rat genomic DNA. One such site was found to reside wit hin the first intron of the cyclin G gene. Cyclin G mRNA levels are st rongly elevated upon induction of wild type p53 activity in cells carr ying a temperature sensitive p53 mutant. The cyclin G gene also carrie s a second p53-binding motif upstream to its transcriptional start sit e. The presence of two high affinity p53-binding sites may confer upon the cyclin G gene the potential to be activated very efficiently by p 53. These data raise the possibility that cyclin G may be a downstream mediator of at least some of the biological effects of p53.