title: GATA4 regulates ANF expression synergistically with Sp1 in a cardiac hypertrophy model.
abstract: Cardiac hypertrophy in response to multiple stimuli has important physiological and pathological significances. GATA4 serves as a nuclear integrator of several signalling pathways during cardiac hypertrophy. Sp1 and Sp3 are also reported to be involved in this process. However, the mechanism by which GATA4 acts as a mediator, integrating these ubiquitously expressed transcriptional factors, is poorly understood. We found that the expression of GATA4 and Sp1 was up-regulated in the myocardium of a pressure overload hypertrophy rat model, as well in phenylephrine-induced (PE-induced) hypertrophic growth of neonatal cardiomyocytes. GST pull-down assays demonstrated that GATA4 could interact with Sp1 in vitro. Therefore, we proposed that GATA4 cooperates with Sp1 in regulating ANF expression, as its reactivation is closely linked with hypertrophy. Further studies demonstrated that GATA4 could activate the ANF promoter synergistically with Sp1 through direct interaction. In contrast, Sp3 exhibited antagonistic function, and overexpression of Sp3 repressed the transcriptional synergy between Sp1 and GATA4. We also found that Sp1 alone could activate the ANF promoter in cardiomyocytes, whereas Sp3 exerted negative effects on ANF expression. Bioinformatics analysis revealed novel Sp-binding sites on the ANF promoter. The recruitment of GATA4 and Sp1 on the ANF promoter was enhanced during phenylephrine-mediated hypertrophy, whereas the recruitment of Sp3 was reduced. The phosphorylation of GATA4 by ERK1/2 kinase could enhance the affinity between GATA4 and Sp1. Thus, our findings revealed the critical interaction of GATA4 and Sp1 in modulating ANF expression, indicating their involvement in cardiac hypertrophy.
authors.affiliation: Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Peking University, Haidian District, Beijing, China.
authors.forename: Xiaoqing
authors.initials: X
authors.lastname: Hu
authors.forename: Tao
authors.initials: T
authors.lastname: Li
authors.forename: Chenguang
authors.initials: C
authors.lastname: Zhang
authors.forename: Yinan
authors.initials: Y
authors.lastname: Liu
authors.forename: Ming
authors.initials: M
authors.lastname: Xu
authors.forename: Weiping
authors.initials: W
authors.lastname: Wang
authors.forename: Zhuqing
authors.initials: Z
authors.lastname: Jia
authors.forename: Kangtao
authors.initials: K
authors.lastname: Ma
authors.forename: Youyi
authors.initials: Y
authors.lastname: Zhang
authors.forename: Chunyan
authors.initials: C
authors.lastname: Zhou
mesh_terms: D000818:Animals; D009320:Atrial Natriuretic Factor / Q000235:genetics* / Q000378:metabolism; D001483:Base Sequence; D001665:Binding Sites; D006332:Cardiomegaly / Q000235:genetics* / Q000473:pathology; D004195:Disease Models, Animal; D050991:GATA4 Transcription Factor / Q000378:metabolism*; D005786:Gene Expression Regulation / Q000187:drug effects; D006367:HeLa Cells; D006801:Humans; D008969:Molecular Sequence Data; D010656:Phenylephrine / Q000494:pharmacology; D010766:Phosphorylation / Q000187:drug effects; D011401:Promoter Regions, Genetic / Q000235:genetics; D011485:Protein Binding / Q000187:drug effects; D051381:Rats; D017207:Rats, Sprague-Dawley; D016329:Sp1 Transcription Factor / Q000378:metabolism*; D051705:Sp3 Transcription Factor / Q000378:metabolism; D014158:Transcription, Genetic / Q000187:drug effects
chemical_list: D050991:GATA4 Transcription Factor; D016329:Sp1 Transcription Factor; D051705:Sp3 Transcription Factor; D010656:Phenylephrine; D009320:Atrial Natriuretic Factor