Structure and expression of the human calcitonin/CGRP genes

Recently, we have reported the isolation of cDNA encoding a second human calcitonin gene-related peptide (hCGRP-II) [(1985) FEBS Lett. 183, 403-407]. In this report we describe the isolation and characterization of the gene encoding hCGRP-II. This gene, designated CALC-II, is structurally closely related to the known CALC-I gene encoding human calcitonin (hCT) and hCGRP-I. In contrast to CALC-I, CALC-II does not seem to be alternatively expressed. The formation of a second, hCT-like mRNA by differential splicing of CALC-II transcripts is unlikely in view of the structure of CALC-II, and could not be demonstrated in tissues known to express CALC-I and CALC-II.