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.