|
Fig. 6 A 3-kb distal element upstream of the proximal promoter region is sufficient to drive expression in both chambers of the heart. (A) Neither the SV40 promoter (construct 2) nor the proximal promoter (construct 4) was capable of providing significant levels of GFP expression in the heart, compared to 12 kb of upstream genomic sequences (construct 1). Similarly, the 4.2-kb distal fragment placed upstream of the SV40 minimal promoter was not sufficient to confer significant GFP expression to the heart (construct 3). However, a subregion of the 4.2-kb sequence containing 3 kb of GATA-4 DNA upstream of the 1.1-kb proximal region of the GATA-4 promoter was sufficient to confer GFP expression to the heart (construct 5). Student's t test was performed in comparison to the 12-kb promoter fragment and a significant difference (P < 0.01) in the ability of a construct to drive GFP expression in the heart is indicated as in Fig. 5. (B) Confocal analysis of an embryo transgenic for the 3-kb distal region from -11 to -8 kb together with the 1.1-kb proximal region of the GATA-4 promoter (germline transmission of construct 5 in A). GFP is expressed in both chambers of the heart recapitulating the results found in A.
Reprinted from Developmental Biology, 267(2), Heicklen-Klein, A., and Evans, T., T-box binding sites are required for activity of a cardiac GATA-4 enhancer, 490-504, Copyright (2004) with permission from Elsevier. Full text @ Dev. Biol.