STRUCTURE OF THE HUMAN GENE ENCODING THE PHOSPHORYLASE-KINASE BETA-SUBUNIT (PHKB)

We have determined the cDNA sequence and the gene structure of the hum an phosphorylase kinase beta subunit (PHKB). With 95% amino acid seque nce identity, the predicted primary structure is highly similar to tha t of the rabbit beta subunit. At least 140 kilonucleotides in length, the gene is large and consists of 33 exons. Exons 26 and 27 are two ho mologous, mutually exclusively spliced exons in the middle of the gene , and exon 2 is a facultatively utilized cassette exon encoding an alt ernative N-terminus of the beta subunit. The previous assignment of th e PHKB gene to chromosome 16 is confirmed by the successful screening of a chromosome 16-specific genomic library. Plaque hybridization at r educed stringency led to the isolation of two processed pseudogenes, P HKBP1 and PHKBP2, but of no other PHKB-related sequences.