MOLECULAR-CLONING OF FKHRL1P2, A MEMBER OF THE DEVELOPMENTALLY-REGULATED FORK HEAD DOMAIN TRANSCRIPTION FACTOR FAMILY

Here we report the expression of a fork head domain protein in human T helper cells. We cloned and characterized a fork head cDNA from human T helper cell mRNA using differential display RT-PCR. The cDNA contai ns a 546-nucleotide (nt) open reading frame (ORF) that codes for the c arboxyl-terminal 180 amino acids (aa) of the recently identified fkhrl 1 gene. This ORF does not contain the characteristic DNA-binding domai n found in members of the forkhead protein family. In-vitro transcript ion/translation of this cDNA expressed a protein of approximately 20 k Da. We have generated antibodies that specifically immunoprecipitated the in-vitro-translated 20-kDa protein. This antibody also recognizes in human T lymphocytes a 70-kDa protein corresponding in size to that predicted for the fkhrl1 gene product. The mRNA levels for fkhrl1 is e levated in T helper-induced lymphocytes in comparison to PHA-stimulate d T lymphocytes. Further characterization of FKHRL1 and its related fa mily members should shed light on the transcriptional mechanisms of th is fork head gene subfamily and their role in T helper cell differenti ation and regulation of cell growth. (C) 1998 Elsevier Science B.V. Al l rights reserved.