Molecular characterization of frog chromogranin B reveals conservation of selective sequences encoding potential novel regulatory peptides1

Chromogranin B (CgB) is a member of the granin family of neuroendocrine secretory proteins, which has been proposed to play a role in secretory granule biogenesis and as a precursor to bioactive peptides. The cloning of CgB in a phylogenetically distant vertebrate, the frog Rana ridibunda, reveals a modest overall homology (35-40%) with mammalian CgB. However, the sequences of the N- and C-terminal regions are more highly conserved (57-65% amino acid identity) and may give rise to novel regulatory peptides. In frog, intense expression of CgB mRNA was observed in particular structures of the brain and in the distal lobe of the pituitary.