A HUMAN FORKHEAD WINGED-HELIX TRANSCRIPTION FACTOR EXPRESSED IN DEVELOPING PULMONARY AND RENAL EPITHELIUM/

Members of the forkhead/winged-helix transcription factor family play crucial roles during vertebrate development. A human hepatocyte nuclea r factor/forkhead homolog (HFH)-4 cDNA encoding a 421-amino acid prote in was isolated from a human fetal lung cDNA library. By Southern blot analysis of human-rodent somatic cell hybrid genomic DNA, the human H FH-4 gene localizes to chromosome 17q23-qter. This is the locus of ano ther forkhead/winged-helix gene, the interleukin enhancer binding fact or gene. RNA blot analysis revealed a 2.5-kilobase human HFH-4 transcr ipt in fetal lung, kidney, and brain as well as in adult reproductive tissues, lung, and brain. By in situ hybridization, HFH-4 expression i s associated with differentiation of the proximal pulmonary epithelium , starting during the pseudoglandular stage of human lung development. During human renal morphogenesis, HFH-4 is expressed in the developin g epithelial cells of the ureteric duct, glomerulus, and epithelial ve sicles. The unique pattern of HFH-4 expression during human fetal deve lopment suggests a role for this forkhead/winged-helix factor during p ulmonary and renal epithelial development.