Cloning, expression and immunolocalization of alpha1-adrenoceptor in different tissues from rhesus monkey and human male reproductive tract

Abstract

This study reports the genomic organization of the rhesus alpha(1A)-adrenoceptor gene (ADRA1A). Full-length cloning of rhesus ADRA1A splice variants was achieved by combining PCR screening of a seminal vesicle cDNA library and 5'-RACE assays with total RNA from seminal vesicle. The classical ADRA1A mRNA (ADRA1A_v1) and six full-length ADRA1A splice variants were identified representing transcripts that code for functional (ADRA1A_v1, ADRA1A_v2a, ADRA1A_v3a, ADRA1A_v3d, ADRA1A_v3e) and truncated (ADRA1A_v2c and ADRA1A_v3c) receptor isoforms. Comparative analysis of the deduced amino acid sequence indicated that rhesus ADRA1A_i1 isoform (corresponding to the ADRA1A_v1 transcript) shares high identity to the amino acid sequence present in the classical alpha(1A)-adrenoceptor from human and other mammalian species. Partial nucleotide sequences for rhesus alpha(1B)-(ADRA1B) and alpha(1D)-adrenoceptor (ADRA1D) transcripts were also characterized. RT-PCR studies indicated differential distribution of all ADRA1A-related splice variants as well as ADRA1B and ADRA1D mRNAs, in tissues from rhesus and human male reproductive tract. Immunohistochemistry revealed alpha(1A)-adrenoceptor (ADRA1A_i1) immunostaining in smooth muscle cells and epithelial cells of rhesus efferent ductules, epididymis and seminal vesicle. Taken together the present results demonstrate that the complexity of the splicing mechanisms involved in the regulation of the ADRA1A gene is not restricted to human and is a common characteristic among Old World monkeys.