MafG-2 is a novel Maf protein that is expressed by stimulation of extracellular H+

We cloned MafG-2, a novel splice variant of MafG, from rat brain by RT-PCR, method, MafG-2 differs from the previously published MafG by an insertion of 27 amino acids. Sequence analysis of the cDNA-encoded MafG-2 showed that MafG-2 contains basic domain and basic, leucine zipper (bZip) motif. Trans ient transfection studies with GFP-MafG-2 chimera protein indicate that Maf G-2 is localized in the nuclei of transfected COS-7 cells. To determine whe ther gene expression of mafG-2 mRNA is induced by an increase in extracellu lar protons, we analyzed expression of the mRNA in PC12 cells after an incr ease in extracellular proton concentration. We found that the mafG-2 mRNA e xpression increased when extracellular pH was decreased gradually from 7.40 to 7.20 and that there was a significant correlation between extracellular pH value and the expression of mafG-2 mRNA. These results suggest that an increase in extracellular proton may induce the expression of mafG-2 mRNA a nd MafG-2 may be involved in signal transduction of extracellular of H+. (C ) 2001 Elsevier Science Inc. All rights reserved.