A GATA-4 mutant lacking p300-induced acetylation suppresses myocardial cell hypertrophy

A GATA-4 mutant lacking p300-induced acetylation suppresses myocardial cell hypertrophy

Tomohide Takaya1, Teruhisa Kawamura1, Tatsuya Morimoto1, Koh Ono2, Toru Kita2, Akira Shimatsu1, Koji Hasegawa1.

  1. Division of Translational Research, Kyoto Medical Center, National Hospital Organization, Kyoto, Japan.
  2. Department of Cardiovascular Medicine, Graduate School of Medicine, Kyoto University, Kyoto, Japan.

第71回日本循環器学会学術集会 (神戸), 2007/03/17 (ポスター).


A zinc finger protein GATA-4 is one of hypertrophy-responsive transcription factors, and increases its DNA-binding and transcriptional activities in response to hypertrophic stimuli in cardiac myocytes. Activation of GATA-4 during this process i mediated, in part, through acetylation by intrinsic histone acetyltransferase such as a transcriptional coactivator p300. However, GATA-4 acetylation targets by p300 during myocardial cell hypertrophy have not been identified. Within GATA-4, nine lysine residues, possible acetylation sites, exist near the two zinc fingers that serve as cofactor- and DNA-binding domains. By mutational analysis, we have found that four lysine residues located at amino acid sequences between 311-322 are required for synergistic activation of atrial natriuretic factor and endothelin-1 promoters by GATA-4 and p300. A tetra-mutant GATA4, in which these four lysine residues are simultaneously substituted with alanines, not only showed lack of p300-induced acetylation, DNA-binding and transcriptional activities, but also inhibited transcriptional activation by wild-type GATA-4. Expression of this tetra-mutant GATA-4 in cultured neonatal cardiac myocytes using a lentivirus vector suppressed phenylephrine-induced increase in cell size and myofibrillar organization. However, the expression did not affect cardiac myocytes at a basal state. Thus, we have identified the most critical lysine residues of p300-mediated acetylation target in GATA-4 and demonstrate that GATA-4 with simultaneous mutation of these sites suppresses hypertrophic responses as a dominant-negative form in cardiac myocytes.