Analysis of Uncharacterized Expression during Mouse Development and Cardiovascular Morphogenesis.

Mammalian and are a homologous pair of uncharacterized, highly conserved genes cloned from fetal and adult brain cDNA libraries. Herein we map the spatiotemporal expression of and mRNA and their expression patterns in postnatal testis, skin, gastrointestinal, and adipose progenitor tissues. Significantly, is present throughout the early stages of mouse heart development, particularly in the second heart field (SHF) lineage as it differentiates from mesenchymal cells into cardiomyocytes. We also show that is expressed within several early neuronal tissues destined to give rise to central, peripheral, and sympathetic nervous system structures. Expression profiling revealed that the paralog is not expressed during the normal developmental process and that expression was noticeably absent from most adult terminally differentiated tissues. Finally, we confirm that a previously uncharacterized CRISPR/CAS-generated mouse mutant allele is hypomorphic.