We report the cloning, genomic organization and sequence of the mouse alpha
-CALC and beta -CALC genes. The two genes share extensive sequence homolog
y. The transcription units of both genes contain 6 exons. Transcripts of th
e alpha -CALC gene were found to alternatively include exon 4 or exons 5 an
d 6. For the beta -CALC gene exon 4 was not detected in transcripts derived
from this gene. The predicted mouse alpha -CGRP was found to be identical
to rat alpha -CGRP, however, beta -CGRP predicted amino acid sequences reve
aled three amino acid differences suggesting these residues are not critica
l to CGRP function.