Intron 1 elements promote erythroid-specific GATA-1 gene expression

The zinc finger protein GATA-1 functions in a concentration-dependent fashi on to activate the transcription of erythroid and megakaryocytic genes. Les s is understood, however, regarding factors that regulate the GATA-1 gene, Presently elements within intron 1 are shown to markedly affect its erythro id-restricted transcription. Within a full-length 6.8-kilobase GATA-1 gene construct (G6.8-Luc) the deletion of a central subdomain of intron 1 inhibi ted transcription greater than or equal to 10-fold in transiently transfect ed erythroid SKT6 cells, and likewise inhibited high-level transcription in erythroid FDCW2ER-GATA1 cells. In parental myeloid FDCER cells, however, l ow-level transcription was largely unaffected by intron I deletions. Within intron 1, repeated GATA and Apl consensus elements in a central region are described which when linked directly to reporter cassettes promote transcr iption in erythroid SKTG and FDCER-GATA1 cells at high rates. Moreover, GAT A-1 activated transcription from this subdomain in 293 cells, and in SKT6 c ells this subdomain footprinted in vivo. For stably integrated GFP reporter constructs in erythroid SKTG cells, corroborating results were obtained. D eletion of intronic GATA and Apl motifs abrogated the activity of G6.8 pEGF P; activity was decreased by 43 and 56%, respectively, by the deletion of e ither motif; and the above 1800-base pair region of intron 1 per se was tra nscribed at rates uniformly greater than G6.8-pEGFP. Also described is the differential utilization of exons la and Ib among primary erythromegakaryoc ytic and myeloid cells.