Biochemical and Biophysical Research Communications
Acetylation and level of mitochondrial transcription factor A in several organs of young and old rats
Section snippets
Materials and methods
Animal samples. Male Wistar rats were maintained two per cage on a 12:12 h light–dark cycle at 25 °C and had access to standard laboratory chow and water ad libitum. All procedures were in accordance with the guiding principles in the care and use of laboratory animals of Bari University. Four rats for each of different ages (6 and 28 month) were killed and four of their own organs (cerebellum, heart, kidney, and liver) were quickly excised, immediately frozen in isopentane cooled by liquid
Acetylation of TFAM
In order to test whether TFAM was acetylated, the protein was purified from liver of 6-month old rat and subjected to MALDI-TOF mass spectrometry. As shown in Fig. 1A mass analysis, using bovine carbonic anhydrase as internal standard, showed a molecular species at m/z 23,721. Other internally calibrated spectra (not shown) resulted in molecular masses from 23,706 to 23,730 Da. The observed mass is significantly above the theoretical average molecular mass of 23,673, supporting the presence of a
Discussion
The results reported in this paper provide further information on qualitative and quantitative changes of TFAM during aging in different rat organs. Post-translational modification of a mitochondrial DNA-binding protein is reported here for the first time. TFAM is acetylated at a single lysine residue and the extent of acetylation does not change substantially with age. Protein acetylation is a regulatory mechanism for the expression of nuclear genes. In particular histone acetylation activates
Acknowledgements
We thank Dr. H. Hinagaki (Department of Chemistry, National Industrial Research Institute of Nagoya, Japan) for the gift of rat TFAM antiserum. This work was supported by Progetto di Ateneo ‘Regolazione della biogenesi mitocondriale mediata da proteine nucleari in diversi sistemi sperimentali,’ by Sigma-Tau Research Program “Effetti dell’acetil-L-carnitina sulla replicazione ed espressione del DNA mitocondriale nel ratto,” and by M.U.R.S.T. project Cluster C03 “Studio di geni di interesse
References (32)
An integrated theory of aging as the result of mitochondrial DNA mutation in different cells
Arch. Gerontol. Geriatr.
(1991)- et al.
Mitochondrial DNA mutations as an important contributor to ageing and degenerative diseases
Lancet
(1989) - et al.
Decline with age of the respiratory chain activity in human skeletal muscle
Biochim. Biophys. Acta
(1994) - et al.
Increased expression of mitochondrial transcription factor A and nuclear respiratory factor-1 in skeletal muscle from aged human subjects
FEBS Lett.
(2001) - et al.
Studies of acetylation and deacetylation in high mobility group proteins. Identification of the sites of acetylation in HMG-1
J. Biol. Chem.
(1979) - et al.
DNA wrapping and bending by mitochondrial high mobility group-like transcritional activator protein
J. Biol. Chem.
(1992) - et al.
Binding human mitochondrial transcription factor A, an HMG box protein, to a four-way DNA junction
Biochem. Biophys. Res. Commun.
(2000) - et al.
Human mitochondrial transcription factor A binds preferentially to oxidatively damaged DNA
Biochem. Biophys. Res. Commun.
(2002) - et al.
Alteration of Mitochondrial DNA and RNA level in human fibroblasts with impaired vitamin B12 coenzyme synthesis
FEBS Lett.
(1998) - et al.
Isolation of a 25-kDa protein binding to a curved DNA upstream the origin of the L strand replication in the rat mitochondrial genome
J. Biol. Chem.
(1996)