Positive and negative cis-acting elements are required for hematopoietic expression of zebrafish GATA-1

GATA-1 is a transcription factor required for development of erythroid cell s. The expression of GATA-1 is tightly restricted to the hematopoietic line age. Using transgene constructs containing zebrafish GATA-1 genomic sequenc es and the green fluorescent: protein (GFP) reporter gene, we previously sh owed that a 5.6-kb enhancer/promoter fragment is sufficient to direct eryth roid specific expression of the GFP. In this study, we used enhancer/promot er fragments containing various deletion and point mutations to further cha racterize the cis-acting elements controlling tissue-specific GATA-1 expres sion. We report here the identification of distinct cis-acting elements tha t cooperate to confer on GATA-1 its hematopoietic expression pattern. A CAC CC box, located 142 bp upstream of the translation start codon, is critical for the initiation of GATA-1 expression. A distal double GATA element is r equired for maintaining and enhancing the hematopoietic expression of GATA- 1. The erythroid-specific activity of the GATA-1 promoter is also enhanced by a 49-bp sequence element located 218 bp upstream of the CACCC element an d a CCAAT box adjacent to the double GATA motif. Finally, the hematopoietic specificity of the GATA-1 promoter is secured by a negative cis-acting ele ment that inhibits expression in the notochord. (C) 1999 by The American So ciety of Hematology.