Rna in polysomes is an inhibitor of manganese superoxide dismutase
rna-binding protein activity.
Chung, David J., and Linda Biadasz Clerch.
Lung Biology Laboratory, Departments of Physiology and Biophysics
and Pediatrics, Georgetown University School of Medicine, Washington,
DC 20007
APStracts 3:0203L, 1996.
A redox-sensitive protein in rat lung binds to the 3_ untranslated
region (3_ UTR) of manganese superoxide dismutase (MnSOD) mRNA; the
activity of this MnSOD RNA-binding protein (MnSOD-BP) is greater in
12,000g supernatant fractions (S12) from neonates than in S12 from
adults (J. Clin. Invest. 92:1278-1281, 1993). To determine the
mechanism underlying this developmental difference, lung subcellular
fractions were tested for their effect on MnSOD-BP activity. Protein
in the 130,000g supernatant (S130) of lung extracts bound the 3_ UTR.
However, the developmental difference in binding was not present in
S130. The 130,000g pellet (P130) did not bind the 3_ UTR; rather, it
contained an inhibitor of MnSOD-BP activity. Addition of P130 to S130
decreased RNA-binding in a dose-dependent manner. Furthermore, adult
P130 was a more potent inhibitor of RNA-binding activity than
neonatal P130. These data indicate the developmental difference in
MnSOD-BP activity is due, in part, to an inhibitor in P130.
Biochemical characterization revealed the inhibitor is an RNA that
may participate in the post-transcriptional control of MnSOD gene
expression.
Received 24 June 1996; accepted in final form 30 October 1996.
APS Manuscript Number L190-6.
Article publication pending Am. J. Physiol. (Lung Cell. Mol.
Physiology).
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 31 December 1996