The organisation of the mouse chromogranin B (secretogranin I) gene

A cosmid clone containing the gene for mouse chromogranin B (secretogranin I), a secretory protein found in secretory granules of most endocrine cells and neurons, was isolated and sequenced. The chromogranin B protein was found to be encoded by 5 exons which correspond to the cleaved signal peptide, the short N-terminal sequence preceding the disulfide-bonded loop structure, the disulfide-bonded loop structure itself, the large, variable region comprising approximately 90% of the protein, and the conserved C-terminal sequence. The promoter region of the chromogranin B gene is very GC-rich and contains a CATAA motif, a cAMP-responsive element and an Sp1 binding site.