RESUMEN
Transcription factor GATA4 is expressed during early embryogenesis and is vital for proper development. In addition, it is a crucial reprogramming factor for deriving functional cardiomyocytes and was recently identified as a tumor suppressor protein in various cancers. To generate a safe and effective molecular tool that can potentially be used in a cell reprogramming process and as an anti-cancer agent, we have identified optimal expression parameters to obtain soluble expression of human GATA4 in E. coli and purified the same to homogeneity under native conditions using immobilized metal ion affinity chromatography. The identity of GATA4 protein was confirmed using western blotting and mass spectrometry. Using circular dichroism spectroscopy, it was demonstrated that the purified recombinant protein has maintained its secondary structure, primarily comprising of random coils and α-helices. Subsequently, this purified recombinant protein was applied to human cells and was found that it was non-toxic and able to enter the cells as well as translocate to the nucleus. Prospectively, this cell- and nuclear-permeant molecular tool is suitable for cell reprogramming experiments and can be a safe and effective therapeutic agent for cancer therapy.
Asunto(s)
Escherichia coli , Factor de Transcripción GATA4 , Línea Celular , Dicroismo Circular , Escherichia coli/química , Escherichia coli/genética , Escherichia coli/metabolismo , Factor de Transcripción GATA4/biosíntesis , Factor de Transcripción GATA4/química , Factor de Transcripción GATA4/genética , Factor de Transcripción GATA4/aislamiento & purificación , Humanos , Estructura Secundaria de Proteína , Proteínas Recombinantes/biosíntesis , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Proteínas Recombinantes/aislamiento & purificaciónRESUMEN
Various stresses on the heart, such as myocardial infarction and hemodynamic overload, activate the sympathetic nervous system and the renin-angiotensin system, ultimately reach the nuclei of cardiomyocytes, and change the pattern of gene expression associated with cardiac hypertrophy. Although present pharmacological therapy for heart failure targets such extracellular molecules, mortality due to heart failure is still high. A zinc finger protein, GATA4, is one of the hypertrophy-responsive transcription factors, forms a functional protein complex with an intrinsic histone acetyltransferase, p300, and regulates pathological cardiac hypertrophy. Disruption of this complex results in the inhibition of cardiac hypertrophy and heart failure in vivo. To establish a more effective therapy for heart failure, we have been analyzing a common nuclear pathway within cardiomyocytes. We identified 73 GATA4 binding proteins by tandem-affinity purification and mass spectrometric analysis. Noble GATA4 binding partners, such as cyclin-dependent kinase-9 (Cdk9: the core factor of positive transcription elongation factor b) and retinoblastoma-association protein 48/46 (RbAp48/46: the co-repressor complexes containing HDAC1/2), regulate the p300/GATA4-mediated signaling pathway and hypertrophic responses. Further analysis of p300/GATA4 complex is expected to identify target molecules for heart failure therapy.