αCGRP and βCGRP transcript amount in mouse tissues of various developmental stages and their tissue expression sites

The calcitonin gene-related peptides (CGRP), αCGRP and βCGRP, have been implicated to play various roles in primates and rodent. However, since the expression information has been limited, in the present study, we measured the amount of gene expression in mouse brain, liver, kidney, heart, and testis at embryonic day (E) 14, E17, postnatal day (P) 1, P7, and adult using real-time PCR, and determined the precise localization of αCGRP and βCGRP sense/antisense transcripts in tissues using in situ hybridization. The sense transcripts of αCGRP and βCGRP were found mainly in brain, and their amount profiles were similar in the course of development: one expression peak was observed at E17 and the other at P7. The amounts of αCGRP transcripts were greater than those of βCGRP transcripts in the range between 3.6 and 31 times. In the E17 and P7 brains, the localization pattern of αCGRP sense transcripts was similar with that of αCGRP antisense transcripts. Fewer transcripts were found in neuroblasts of E17 corpus callosum, and neuroblasts of P7 corpus callosum, olfactory bulb, plexus chorioideus, and ventriculus lateralis than in other brain areas. The localization pattern of βCGRP sense and antisense transcripts was similar to that for αCGRP except that the βCGRP antisense transcripts showed spot-like localizations. Additionally, the αCGRP sense transcript, and βCGRP sense and antisense transcripts were found in parafollicular cells (C cells) of E17 thyroid lobe. These findings together indicate that αCGRP and βCGRP have their own roles in the ontogenic process.