THYROID-HORMONE REGULATES THE ACETYL-COA CARBOXYLASE PI PROMOTER

The acetyl-CoA carboxylase-alpha gene has two promoters, PI and PII. A variety of mRNA products result from this gene, depending on promoter usage and splicing events. We have investigated thyroid hormone regul ation of acetyl-CoA carboxylase-alpha gene expression, using the rever se-transcription polymerase chain reaction with PI- or PII-specific pr imers. RNA was extracted from a range of tissues taken from hypo-, eu- , or hyperthyroid rats. PII-generated products were found in all tissu es examined at similar levels and were not affected by thyroid state. Products derived from PI were also widely found but with more variable levels of expression. PI mRNAs were reduced in hypo- and elevated in hyperthyroid Livers. In brown adipose tissue, more PI products were fo und in hypothyroid animals. Thus, thyroid hormone regulates the activi ty of the acetyl-CoA carboxylase PI promoter to influence fatty acid s ynthesis in a tissue specific manner. (C) 1998 Academic Press.