Amplification and overexpression of TGIF2, a novel homeobox gene of the TALE superclass, in ovarian cancer cell lines

Homeodomain transcription factors play important roles in directing cellula r proliferation and differentiation. A TALE-superclass homeodomain protein, multifunctional repressor of TGF beta-induced transcription. Here we repor t identification of TGIF2, a novel TALE-superclass homeodomain protein that shows distinct homology with TGIF, especially in its DNA-binding domain. T GIF2 is expressed ubiquitously in human tissues, with the highest levels be ing found in heart, kidney, and testis. The TGIF2 product contains a putati ve nuclear localization signal; translocation of the protein to the nucleus was confirmed by transfection of epitope-tagged cDNA, TGIF2 lies on chromo some 20q11.2-12. Since amplification of 20q is often observed among ovarian cancers, we determined the status of DNA copy-number and expression of TGI F2 in 14 ovarian-cancer cell lines, This gene was overexpressed in all line s that showed amplification by FISH analysis. The results suggested that TG IF2 may play an important role in the development and/or progression of som e ovarian tumors through a mechanism of gene amplification. (C) 2000 Academ ic Press.