Genomic organization and chromosomal assignment for a serine protease gene (CSPB) expressed by human cytotoxic lymphocytes.

The human cytotoxic serine protease ("granzyme") B gene has been isolated and sequenced. The gene is approximately 3500 bp in length and consists of five exons and four intervening introns. Its organization therefore conforms closely to that of the previously cloned serine protease genes which are expressed in mouse cytotoxic lymphocytes and rat mast cells. The 5' upstream region is characterized by an atypical "TATA"-like transcriptional promoter and by a stretch of nucleotides bearing similarity to an enhancer core sequence believed to be requisite for the tissue-specific expression of serine protease genes in the exocrine pancreas. It has previously been demonstrated that mRNA transcripts from the human serine protease B gene are heterogeneous in size, due to frequent faulty intron/exon splicing. Two cryptic splice sites, which are used to generate these aberrant mRNA transcripts, have been identified. Using DNA blot analysis of a panel of human-rodent somatic cell lines, the human serine protease B gene has been localized to chromosome 14.