AF17 Competes with AF9 for Binding to Dot1a to Up-regulate Transcription of Epithelial Na+ Channel α

摘要: We previously reported that Dot1a·AF9 complex represses transcription of the epithelial Na+ channel subunit α (α-ENaC) gene in mouse inner medullary collecting duct mIMCD3 cells and kidney. Aldosterone relieves this repression by down-regulating through various mechanisms. Whether these mechanisms are sufficient conserved human or can be applied to other aldosterone-regulated genes remains largely unknown. Here we demonstrate embryonic kidney 293T express three ENaC subunits all transcriptional regulators examined. These respond aldosterone display benzamil-sensitive currents, as measured whole-cell patch clamping. also show AF17 AF9 competitively bind same domain Dot1a multiple assays have antagonistic effects on expression an α-ENaC promoter-luciferase construct. Overexpression decreased mRNA their reduced currents. overexpression caused opposite effects, accompanied redirection from nucleus cytoplasm reduction histone H3 K79 methylation. The nuclear export inhibitor leptomycin B blocked effect hypomethylation. RNAi-mediated knockdown yielded enrichment hypermethylation. As with AF9, displays cytoplasmic co-localization Sgk1. Therefore, competes Dot1a, decreases possibly facilitating its export, Dot1a·AF9-mediated target genes.