Vol. 289, Issue 3, 1559-1563, June 1999

Na⁺, K⁺-ATPase Inhibitors Down-Regulate Gene Expression of the Intracellular Signaling Protein 14-3-3 in Rat Lens¹

Michelle H. McGowan² , Paul Russell, Deborah A. Carper and David Lichtstein

Laboratory of Mechanisms of Ocular Diseases, National Eye Institute, Bethesda, Maryland (M.H.M., P.R., D.A.C.) and the Department of Physiology, The Hebrew University-Hadassah Medical School, Jerusalem, Israel (D.L.)

To identify genes that are differentially expressed by Na⁺, K⁺-ATPase inhibitors, we used the differential display technique to compare mRNA expression patterns in rat lens. Lenses were treated with 10 µM ouabain, bufalin, or 19-norbufalin derivative for 24 h and were compared with control lenses. Differential display analysis revealed that one of the down-regulated genes was 14-3-3 . Down-regulation was confirmed by Northern blot and by reverse transcription-polymerase chain reaction analysis. Reverse transcription-polymerase chain reaction of additional 14-3-3 isoforms revealed that the  and  isoforms of 14-3-3 are also down-regulated by ouabain, bufalin, and 19-norbufalin derivative, whereas the zeta isoform is down-regulated only by bufalin. Down-regulation of the 14-3-3 isoforms occurred without a significant change in -crystallin gene expression. These results demonstrate that one of the consequences of Na⁺, K⁺-ATPase inhibition by exogenous or endogenous inhibitors is the down-regulation of mRNA transcripts encoding several isoforms of 14-3-3. Because the 14-3-3 proteins are multifunctional regulatory proteins, the reduction in the abundance of various isoforms will have profound effects on cell function.