THE MITOCHONDRION AS A PRIMARY SITE OF ACTION OF GLUCOCORTICOIDS - MITOCHONDRIAL NUCLEOTIDE-SEQUENCES, SHOWING SIMILARITY TO HORMONE RESPONSE ELEMENTS, CONFER DEXAMETHASONE INDUCIBILITY TO CHIMERIC GENES TRANSFECTED IN LATK(-) CELLS

The hypothesis of a primary action of steroid hormones on mitochondria l gene expression has been supported by the detection of the glucocort icoid receptor in liver mitochondria and the demonstration of the inte raction of the receptor with putative mitochondrial HREs. We now show that two putative mitochondrial glucocorticoid response elements prese nt within the cytochrome oxidase subunit I gene (GREI and GREII), link ed to a thymidine kinase promoter and to the CAT gene, transfected to LATK(-) cells, confer dexamethasone inducibility to the CAT gene. As t he plasmids were stably transfected, hormone induction was analysed in the nuclear background. This effect is dose dependent and is abolishe d by the glucocorticoid antagonist RU38486. (C) 1997 Academic Press.