Increased expression of mitochondrial transcription factor A and nuclear respiratory factor-1 in skeletal muscle from aged human subjects

The expression of two factors involved in the nuclear-mitochondrial crosstalk, namely the mitochondrial transcription factor A (TFAM) and the nuclear respiratory factor-1 (NRF-1), was studied in human skeletal muscle biopsies of young and aged subjects. Aged subjects presented a 2.6-fold and an 11-fold increase of the levels of TEAM protein and TEAM mRNA, respectively. The increased expression of TEAM was associated to the doubling of NRF-1 DNA-binding affinity and to a 6-fold increase of NRF-1 mRNA level, The upregulation of TEAM and NRF-1, in aged skeletal muscle, appears involved in the pathway leading to the age-related increase of mitochondrial DNA content. (C) 2001 Federation of European Biochemical Societies, Published by Elsevier Science B.V. All rights reserved.