Endothelin‐converting enzyme‐1 is a downstream target of the homeobox transcription factor Nkx2‐5

Autor: A. Thomas, Julia Lemmer, Hans-Dieter Orzechowski, Martin Paul, S. D. Kovacevic, M. Strasdat, T. Behrouzi, Heiko Funke-Kaiser, C. V. Langsdorff, Frank S. Zollmann
Rok vydání: 2003
Předmět:
Zdroj: The FASEB Journal. 17:1-26
ISSN: 1530-6860
0892-6638
DOI: 10.1096/fj.02-0700fje
Popis: The homeobox transcription factor Nkx2-5 and the zinc metalloprotease endothelin-converting enzyme-1 (ECE-1) are essential for cardiac development. Here, we demonstrate for the first time a functional link between Nkx2-5 and ECE-1. In transiently transfected rat H9c2 cardiomyoblasts, the alternative promoters specific for ECE-1a, ECE-1b, and ECE-1c are activated by Nkx2-5 coexpression. Lack of a consensus sequence for Nkx2-5 binding within the ECE-1c promoter and mutational analyses of Nkx2-5 consensus sequences identified in the ECE-1a and ECE-1b promoters, respectively, reveal an indirect mechanism of activation that is supported by gel shift assays. Furthermore, we have evidence of an additional direct activation mechanism of the ECE-1b promoter by Nkx2-5. With the use of RNase protection assay, Northern blot, and real-time PCR, the activating effect of Nkx2-5 on mRNA expression of ECE-1 isoforms was confirmed in the chromatin context of H9c2 and endothelial EA.hy926 cells, respectively, by stable Nkx2-5 overexpression. The interaction presented in this work provides a possible explanation for distinct phenotypic aspects of patients carrying mutations in the Nkx2-5 gene and may also be of significance for the pathophysiology of heart failure.
Databáze: OpenAIRE
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