Fig. 11. GATA6 activates the mouse Aqp5 promoter. (A) Representation of the two regions of the mouse Aqp5 promoter used in the trans-activation assays with the full length –1437 bp region containing four putative GATA DNA binding sites (ovals) and the –503 bp region lacking all four putative GATA binding sites. Homology of GATA DNA binding site 1 and site 2 between the mouse and rat Aqp5 promoters are also shown with the consensus GATA DNA binding sequence underlined. Note that site 2 is on the antisense strand. (B) NIH-3T3 cells were transfected with either the pGL3/Aqp5/–1.4 or pGL3/Aqp5/–0.5 reporter constructs, the pcDNA3 plasmid or the pcDNAG6 expression construct and the pMSVß-gal control plasmid as indicated. Background luciferase activity is normalized to either of the reporter vectors co-transfected with the pcDNA3 vector lacking the GATA6 cDNA. (C) The GATA6/En fusion protein represses GATA6-dependent trans-activation of the mouse Aqp5 promoter. Sub-maximal levels of pcDNA3G6 expression plasmid (1 µg) were transfected into NIH-3T3 cells along with increasing amounts of the pcDNA3G6/En, pcDNA3G6mut/En, or pcDNA3En expression plasmids as well as the pMSVß-gal control plasmid as indicated. Background luciferase activity was normalized to the reporter vectors co-transfected with the insertless pcDNA3 vector. Data is represented as fold activation above background and is the average of three experiments ±s.e.m.