Differential expression of nuclear receptor coregulators in mouse tissues

Abstract

Nuclear receptor coregulators, including co-activators, co-repressors and co-activator binding proteins, play an important role in nuclear receptor activation and target gene transcription. Coregulators are diverse proteins with various functional domains, which can bind directly or indirectly to canonical nuclear receptors and form protein complexes on respective target gene responsive elements, to regulate transcription. The activation of nuclear receptor in vivo is regulated at different levels. Competition between different nuclear receptors for common limiting coregulators is one among those. For a clear understanding of the differential expression of common nuclear receptor coregulators and their role in regulation of nuclear receptor function in normal mice, we have analyzed the gene expression of nuclear receptor co-activators PBP/TRAP220, PRIP/ASC-2, CBP, SRC-1/p160, PRIC285, PRIC320 and co-activator binding proteins CARM-1 and PIMT at mRNA level by quantitative PCR (QPCR). The cDNAs for QPCR were derived from pooled tissue samples of C57BL/6J mice. Our results clearly showed differential expression of these genes in vivo, in that brain abundantly expresses SRC-1, CBP, PIMT and PRIC320 and testis expresses the most PBP. CARM-1 and PRIP were expressed more in both brain and testis. Heart and skeletal muscle expressed more CARM-1 and modest amount of PIMT, CBP and PBP. PRIC285 is highly expressed in liver, small intestine and adipose tissues. This study will help us to better understand the function of these coregulators and the complexity of nuclear receptor activation in vivo. (This work was supported by NIH)