CtBP1 interacts with the N-terminal region of FANCC in yeast. (A) Schematic representation of the mammalian protein CtBP1. Two isoforms (CtBP1-L and CtBP1-S) are generated by two mRNA splice variants. The various CtBP1 domains are indicated; these include a D-isomer–specific 2-hydroxy acid dehydrogenase domain (D2-HDH), PLDLS-binding sites, a dimerization domain, and an RRT-binding groove. Phosphorylation sites are shown as circles. The CtBP1 clone obtained from yeast screening corresponds to amino acids 175-440. (B) Yeast 2-hybrid assay with FANCC and CtBP1^175-440 proteins. The AH109 yeast strain was co-transformed with FANCC constructs expressing full-length or truncated FANCC as baits and with CtBP1^175-440 as prey and was assayed for interaction by plating with dropout medium lacking tryptophan, leucine, histidine, and adenine (−WLHA). Negative and positive interactions are indicated as (−) and (+), respectively. The negative controls include CtBP1^175-440 cotransformed with the empty bait vector. Positive controls include p53 bait and SV40 T antigen prey vectors (not shown). Each experiment was performed a minimum of 3 times in triplicate with each gene cloned into either the bait or prey vector.