alpha 1-Adrenergic receptors (alpha 1-ARs) play critical roles in the regul
ation of a variety of physiological processes. Increasing evidence suggests
that multiple receptor subtypes of alpha 1-ARs regulate these physiologica
l processes. Molecular cloning has identified three distinct cDNAs encoding
alpha 1-AR subtypes (alpha 1A, alpha 1B and alpha 1D) that are structurall
y homologous. Among the alpha 1-AR subtypes, the function of the alpha 1D-A
R remains unclear. In order to examine the physiological role of alpha 1D-A
R, we cloned and characterized a gene for the mouse alpha 1D-AR. Using a mo
use alpha 1D-AR cDNA as a probe, we isolated the gene for the mouse (alpha
1D-AR from a mouse genomic Library. The alpha 1D-AR consists of two exons a
nd an intron that interrupts the coding region of the putative sixth transm
embrane domain. The 5'-flanking region of exon 1 contains neither a TATA bo
x nor a CAAT box but is high in GC content and contains several Spl binding
sites (GC boxes). This pattern is similar to promoters described for other
members of alpha 1-ARs. The untranslated region also contains putative cyc
lic AMP response elements. Isolation of this gene will allow further invest
igation, via gene knock-outs and deletion mutants, of the mechanisms of tra
nscriptional regulation and a greater understanding of the physiological ro
le of alpha 1D-AR.