Multiple forms of the mouse TGIF2 protein. A) alignment of human TGIF2 and mouse Tgif2 and Tgif2d protein sequence. Differences between human and mouse are shaded. Dashes indicate amino acids missing in mTGIF2d. The homeodomain and carboxyl-terminal extension are boxed. The carboxyl-terminal region of TGIF2 which is conserved in TGIF is indicated by a dashed box. MAP kinase phosphorylation sites are boxed, and threonine to valine mutations are indicated below. B) Alignment of the carboxyl-terminal part of the homeodomain and extension from TGIFs of different species. TGIF2: human, mouse; TGIF: human, mouse, chicken, Xenopus, zebra fish; Drosophila dTGIFa and dTGIFb. Residues identical between all are shaded black, similar are gray. The homeodomain is boxed and the arrow indicates the position affected by alternate splicing of mTgif2. COS-1 cells were transfected with the indicated Flag-tagged expression constructs (C) or with Flag-mTGIF2 or a mutant in which two threonines were altered to valine (D). Protein expression was analyzed by western blotting with a Flag specific antibody.