Cell and Transport PhysiologySilencing of TonEBP/NFAT5 Transcriptional Activator by RNA InterferenceNa, Ki Young; Woo, Seung Kyoon; Lee, Sang Do; Kwon, H. Moo Author Information Division of Nephrology, Johns Hopkins University, Baltimore, Maryland. Correspondence to Dr. H. Moo Kwon, Nephrology, N3W143, University of Maryland, 22 South Greene St., Baltimore, MD 21201. Phone: 410-706-4382; Fax: 410-706-4314; Accepted October 18, 2002 Received September 16, 2002 Journal of the American Society of Nephrology 14(2):p 283-288, February 2003. | DOI: 10.1097/01.ASN.0000045050.19544.B2 Buy Metrics Abstract ABSTRACT. TonEBP is a transcriptional activator that is expressed throughout development in many tissues and cell types. In the kidney medulla, TonEBP appears to be an important local regulator of differentiation by virtue of stimulating several genes. To study the function of TonEBP, two small interfering RNA (siRNA) duplexes were developed that reduced TonEBP expression effectively via RNA interference. The silencing lasted only 3 d after introduction of the TonEBP-siRNA’s. As expected, TonEBP-driven reporter gene expression and expression of the sodium/myo-inositol cotransproter (SMIT), aldose reductase (AR) and heat shock protein 70 (HSP70) mRNA were significantly decreased in cells where TonEBP expression was silenced. These data provide direct evidence that the SMIT, AR, and HSP70 genes are targets of TonEBP, although the potential role of other proteins, such as accessory proteins, cannot be excluded. The TonEBP-siRNA is an effective tool that should prove useful in the investigation of loss-of-function relationship in cells. E-mail: [email protected] Copyright © 2003 The Authors. Published by Wolters Kluwer Health, Inc. All rights reserved.