Genomic organization, promoter analysis, and chromosomal mapping of the mouse gene encoding Cdk9

Cdk9, previously known as PITALRE, belongs to the Cdc2 family of protein kinases. We report the isolation and characterization of the complete gene coding for the murine Cdk9 protein. The gene contains seven exons spanning over 6 kb of genomic DNA, and the exon/intron boundaries conformed to the GT/AG rule. The Cdk9 gene mapped on mouse chromosome 2, which is consistent with the known region of synteny with human chromosome 9q34.1. The length of the individual exons ranged from 82 to 850 bp, and introns ranged from 452 to 1,465 bp. The further 5' flanking region of the gene showed features of a housekeeping promoter, such as the lack of a canonical TATA box and the presence of a CCAAT box as well as several GC boxes, which are potential binding sites for numerous transcription factors. Additionally, we performed a basic analysis of the transcriptional activity of the promoter and found that the 364 bp of Cdk9 5' flanking region were able to elicit high transcriptional levels of a luciferase reporter gene in NIH3T3 cells. This study provides the molecular basis for understanding the transcriptional control of the Cdk9 gene, and could serve to facilitate the molecular genetic investigation of Cdk9 function during mouse embryonal development.