CLONING AND CHARACTERIZATION OF FREAC-9 (FKHL17), A NOVEL KIDNEY-EXPRESSED HUMAN FORKHEAD GENE THAT MAPS TO CHROMOSOME 1P32-P34

We describe the cloning of a near full-length cDNA of 4258 nucleotides encoding freac-9 (HGMW-approved symbol FKHL17), a novel human forkhea d gene, The 5 ' untranslated region is unusual since it is very long, 2127 nucleotides, and contains 15 upstream AUG codons, Hybridization t o a panel consisting of RNA derived horn 50 different tissues showed t hat freac-9 is transcribed exclusively in the kidney, The kidney-deriv ed cell lines COS-7 and 293 are shown to express freac-9. A combinatio n of fluorescence in situ hybridization and somatic cell hybrids local izes freac-9 to the chromosomal region of 1p32-p34. The conceptual tra nslation product predicts a protein of 372 amino acids with an N-termi nal domain rich in acidic amino acids and with a high likelihood of fo rming an amphipatic helix, a DNA binding forkhead domain, and a C-term inal region that has a high probability of forming an amphipatic beta- sheet. The amino acid sequence of the DNA binding forkhead motif of FR EAC-9 is identical to that of another forkhead protein, FREAC-4, where as 12 substitutions are present at the nucleotide level. Ther-e are no similarities in regions outside of the DNA binding domains of FREAC-9 and FREAC-4 and since freac-4 maps to a different chromosome (5q12-q1 3) it is likely that sill evolutionary selection has acted to maintain identical DNA binding domains between these two kidney expressed tran scription factors. (C) 1997 Academic Press.