RESUMO
Gata3 acts as a master regulator for T helper 2 (Th2) cell differentiation by inducing chromatin remodeling of the Th2 cytokine loci, accelerating Th2 cell proliferation, and repressing Th1 cell differentiation. Gata3 also directly transactivates the interleukin-5 (Il5) gene via additional mechanisms that have not been fully elucidated. We herein identified a mechanism whereby the methylation of Gata3 at Arg-261 regulates the transcriptional activation of the Il5 gene in Th2 cells. Although the methylation-mimicking Gata3 mutant retained the ability to induce IL-4 and repress IFNγ production, the IL-5 production was selectively impaired. We also demonstrated that heat shock protein (Hsp) 60 strongly associates with the methylation-mimicking Gata3 mutant and negatively regulates elongation of the Il5 transcript by RNA polymerase II. Thus, arginine methylation appears to play a pivotal role in the organization of Gata3 complexes and the target gene specificity of Gata3.
Assuntos
Arginina/genética , Metilação de DNA , Fator de Transcrição GATA3/genética , Interleucina-5/genética , Células Th2/metabolismo , Ativação Transcricional , Sequência de Aminoácidos , Animais , Arginina/metabolismo , Western Blotting , Diferenciação Celular , Proliferação de Células , Células Cultivadas , Chaperonina 60/antagonistas & inibidores , Chaperonina 60/genética , Chaperonina 60/metabolismo , Montagem e Desmontagem da Cromatina , Imunoprecipitação da Cromatina , Citocinas/genética , Citocinas/metabolismo , Citometria de Fluxo , Imunofluorescência , Fator de Transcrição GATA3/metabolismo , Imunoprecipitação , Interleucina-5/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Proteínas Mitocondriais/antagonistas & inibidores , Proteínas Mitocondriais/genética , Proteínas Mitocondriais/metabolismo , Dados de Sequência Molecular , Regiões Promotoras Genéticas/genética , RNA Mensageiro/genética , RNA Interferente Pequeno/genética , Reação em Cadeia da Polimerase em Tempo Real , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Homologia de Sequência de Aminoácidos , Células Th1/imunologia , Células Th1/metabolismo , Células Th2/imunologiaRESUMO
GATA-binding protein 3 (Gata3) controls the differentiation of naive CD4 T cells into T helper 2 (Th2) cells by induction of chromatin remodeling of the Th2 cytokine gene loci, direct transactivation of Il5 and Il13 genes, and inhibition of Ifng. Gata3 also facilitates Th2 cell proliferation via additional mechanisms that are far less well understood. We herein found that Gata3 associates with RuvB-like protein 2 (Ruvbl2) and represses the expression of a CDK inhibitor, cyclin-dependent kinase inhibitor 2c (Cdkn2c) to facilitate the proliferation of Th2 cells. Gata3 directly bound to the Cdkn2c locus in an Ruvbl2-dependent manner. The defect in the proliferation of Gata3-deficient Th2 cells is rescued by the knockdown of Cdkn2c, indicating that Cdkn2c is a key molecule involved in the Gata3-mediated induction of Th2 cell proliferation. Ruvbl2-knockdown Th2 cells showed decreased antigen-induced expansion and caused less airway inflammation in vivo. We therefore have identified a functional Gata3/Ruvbl2 complex that regulates the proliferation of differentiating Th2 cells through the repression of a CDK inhibitor, Cdkn2c.