THE BASIC FIBROBLAST GROWTH-FACTOR (FGF-2) ANTISENSE RNA (GFG) IS TRANSLATED INTO A MUTT-RELATED PROTEIN IN-VIVO

The basic fibroblast growth factor (FGF-2) gene is transcribed bidirec tionally to yield multiple sense (coding) transcripts and a unique 1.5 kb antisense transcript which may regulate sense RNA stability. The a ntisense RNA also contains a long open reading frame that predicts a h ypothetical protein with homology to the prokaryotic MutT antimutator proteins. However, translation of this protein has not previously been demonstrated. We employed antibodies against the conserved MutT-domai n of the deduced human FGF-2 antisense protein (GFG) to demonstrate ex pression of an immunoreactive 24 kDa protein in liver extracts from Xe nopus laevis, and two proteins of 28 and 35 kDa in rat liver. In rats, GFG protein expression detected by western blot was tissue-specific a nd correlated with the level of FGF-2 antisense mRNA expression. These findings demonstrate that, in addition to its possible RNA regulatory function, the FGF-2 antisense transcript is translated into a conserv ed MutT-related protein. (C) 1996 Academic Press, Inc.