The investigator has previously identified an erythroid cell specific transcription factor (erythroid Kruppel-like factor:EKLF) whose molecular and biological properties suggest that it is intimately involved in the regulation of erythroid specific gene expression. Preliminary experiments indicate that the EKLF promoter contains elements that are active only in erythroid cells and that steady state EKLF message levels can be induced to high levels by erythropoietin. The proposed studies of the EKLF promoter may thus illuminate how erythroid cell specific production of an intracellular regulatory molecule is accomplished and is related to signals from extracellular erythropoietin. The regulation of EKLF expression will be addressed by identification of its erythroid specific promoter elements and isolation of their cognate DNA binding proteins and additionally by monitoring whether these elements generate correct onset and localization of a linked reporter gene during embryogenesis. The mechanism of induction of EKLF by erythropoietin will be probed by kinetic and transcriptional tests of its activation, by localization of the erythropoietin response element and identification of its binding protein and by determining its involvement in the transduction (possibly via JAK2) of the extracellular erythropoietin signal.
