CLONING AND CHARACTERIZATION OF 3 HUMAN FORKHEAD GENES THAT COMPRISE AN FKHR-LIKE GENE SUBFAMILY

Alveolar rhabdomyosarcomas are associated with unique chromosomal tran slocations t(2;13) and t(1;13), which arise from fusion of the genes f or the paired box proteins PAX3 and PAX7, respectively, to the FKHR (f orkhead in rhabdomyosarcoma) gene on chromosome 13q14. Here we report the identification and characterization of three novel human forkhead genes with similarity to FKHR. The three genes (HGMW-approved symbols FKHRP1, FKHRL1, and FKHRL1P1) map to chromosomal regions 5q35.2-q35.3, 6q21, and 17p11, respectively. Based on amino acid sequence compariso ns of their forkhead domains, FKHRL1, FKHRL1P1, and FKHRP1 share 86, 8 4, and 68% identity, respectively, with FKHR. While FKHR and FKHRL1 ar e expressed in every human adult tissue examined, FKHRP1 mRNA expressi on could not be detected, and FKHRL1P1 expression was present only at low levels. FKHR and FKHRL1 share a similar genomic organization, each having a very large intron 1 (FKHR similar to 130 kb and FKHRL1 >90 k b), which bisects their respective forkhead domains at identical posit ions, as well as a second intron just downstream of each stop codon. F KHRP1 and FKHRL1P1 lack introns and contain stop codons that prevent t hem from yielding full-length proteins. Thus, while FKHR and FKHRL1 re present functional genes, FKHRP1 and FKHRL1P1 probably are processed p seudogenes. These results suggest that these four genes represent an F I(HR-like gene subfamily within the larger human forkhead gene family. (C) 1998 Academic Press.