Evidence of tissue-specific, post-transcriptional regulation of NRE-2 expression

Mitochondrial respiratory function requires the expression of genes both fr om the mitochondrial and nuclear genomes. Nuclear respiratory factor 2 (NRF -2) is a transcription factor required for the expression of several nuclea r-encoded mitochondrial proteins, including the specific mitochondrial tran scription factor Tfam. This makes NRF-2 a likely candidate to coordinate ex pression of mitochondrial components. NRF-2 is a multisubunit complex of wh ich the a subunit binds DNA and the beta subunit enhances this binding, res pectively. We have analysed in vivo the expression patterns of NRF-2 subuni ts both at the mRNA and protein level, in three rat tissues, Liver, testis and brain. In contrast with Tfam or the 'housekeeping' beta -actin expressi ons in which a parallel gradient was observed, no correlation was found bet ween NRF-2 mRNAs and proteins levels, thus suggesting post-transcriptional regulation. (C) 2000 Societe francaise de biochimie et biologie moleculaire / Editions scientifiques et medicales Elsevier SAS.