ANALYSIS OF THE 5' FLANKING SEQUENCES FROM THE HUMAN PROTEIN-KINASE-P58 (PITSLRE-BETA-1)-ENCODING GENE

The p58 (PITSLRE beta 1) protein kinase (PK) is a member of a large supergene family related to the master mitotic protein kinase, p34(cdc2). This PK is also a member of a sub-family itself, with at least six additional related PITSLRE PK isoforms expressed by alternative splicing and promoter utilization from three duplicated genes. Minimal overproduction of the PITSLRE beta 1 PK in Chinese hamster ovary cells results in a late mitotic delay, suggesting that this PK's function may be related to the cell cycle [Bunnell et al., Proc, Natl. Acad. Sci. USA 87 (1990) 7467-7471]. Further studies using structural and functional mutants have shown that PITSLRE PKs are involved in signaling apoptosis. The gene encoding the PITSLRE beta 1 PK has previously been isolated and structurally characterized [Eipers et al., Genomics 13 (1992) 613-621]. Here we characterize the minimal essential promoter for this gene. Analysis of a 1.18-kb stretch of DNA located upstream from the PITSLRE beta 1 start codon demonstrates that significant cat gene expression can be driven by a construct containing this sequence. Deletion studies of this DNA fragment have defined a minimal promoter that extends 144 bp 5' of the previously mapped transcription start point (tsp), and 521 bp 5' of the start codon. This region of PITSLRE beta 1 DNA does not contain canonical TATA-box sequences or G+C-rich sequences associated with many promoters, yet it has approximately 20% of the promoting activity when compared to the SV40 early promoter. This suggests that this DNA sequence is a relatively strong basal promoter of a previously uncharacterized type.