D. Freyssenet et al., Cytochrome c transcriptional activation and mRNA stability during contractile activity in skeletal muscle, AM J P-ENDO, 40(1), 1999, pp. E26-E32
Citations number
36
Categorie Soggetti
Endocrinology, Nutrition & Metabolism
Journal title
AMERICAN JOURNAL OF PHYSIOLOGY-ENDOCRINOLOGY AND METABOLISM
We evaluated contractile activity-induced alterations in cytochrome c trans
criptional activation and mRNA stability with unilateral chronic stimulatio
n (10 Hz, 3 h/day) of the rat tibialis anterior (TA) muscle for 1, 2, 3, 4,
5, and 7 days (n = 3-11/group). Transcriptional activation was assessed by
direct plasmid DNA injection into the TA with a chloramphenicol acetyltran
sferase (CAT) reporter gene linked to 326 bp of the cytochrome c promoter.
Cytochrome c mRNA in stimulated muscles increased by 1.3- to 1.7-fold above
control between 1 and 7 days. Cytochrome c protein was increased after 5 d
ays of stimulation to reach levels that were 1.9-fold higher than control b
y 7 days. Cytochrome c mRNA stability, determined with an in vitro decay as
say, was greater in stimulated TA than in control between 2 and 4 days, lik
ely mediated by the induction of a cytosolic factor. In contrast, cytochrom
e c transcriptional activation was elevated only after 5 days of stimulatio
n when mRNA stability had returned to control levels. Thus the contractile
activity-induced increase in cytochrome c mRNA was due to an early increase
in mRNA stability, followed by an elevation in transcriptional activation,
leading to an eventual increase in cytochrome c protein levels.