Molecular characterization of a novel gene family (PHTF) conserved from Drosophila to mammals

PHTF1 (putative homeodomain transcriptional factor; HGMW-approved symbol PH TF1) is a putative homeobox gene located at band 1p11-p13 of the human geno me, We report here the cloning and sequencing of its mouse and Drosophila o rthologs. The conservation between mouse and human proteins extends over th e entire protein and is localized at the putative homeodomain and at the N- and C-terminal regions of Drosophila protein sequence. Blast searches allo wed us to identify another member of the PHTF family, PHTF2, located at 7q1 1.23-q21 of the human genome. The strongest homologies between human PHTF1 and PHTF2 are localized to the domains that we already described in Drosoph ila, i.e,, the putative homeodomain and the N- and C-terminal regions. The human and mouse genes display 98% similarity to one another, 56% similarity with the Drosophila gene, and 67% similarity with PHTF2, suggesting that p htf might define a novel gene family of highly divergent homeobox genes. Fi nally, Northern blot analysis showed that while PHTF1 is expressed mainly i n testis, PHTF2 is predominantly expressed in muscle, suggesting that these two genes may have acquired different functions after their duplication an d divergence. (C) 2000 Academic Press.