We describe a novel erythroid cell-specific
cDNA (
EKLF [erythroid Krüppel-like factor]) isolated by enriching for genes expressed in a mouse
erythroleukemia cell line but not expressed in a mouse monocyte-macrophage cell line. The complete
cDNA sequence is predicted to encode a
protein of approximately 38,000 Da that contains a
proline-rich amino domain and three
TFIIIA-like zinc fingers within the carboxy domain. Additional sequence analyses reveal that the
EKLF zinc fingers are most homologous to the Krüppel family of
transcription factors and also allow us to predict potential
DNA-binding target sites for the
EKLF protein. On the basis of this prediction, we show that
EKLF is able to bind the sequence CCA CAC CCT, an essential
element of the
beta-globin promoter. Its tissue distribution establishes that the
EKLF transcript is expressed only in bone marrow and spleen, the two hematopoietic organs of the mouse, and analysis of murine cell lines indicates that
EKLF expression is limited to erythroid and mast cell lines. Cotransfection assays establish that
EKLF transcriptionally activates a target promoter that contains its
DNA-binding site. The tissue expression pattern of
EKLF, in conjunction with its function as a transcriptional activator, strongly suggests that the
EKLF protein may be intimately involved in establishment and/or maintenance of the erythroid cell phenotype.