This family consists of several bacterial VirC1 proteins. In Agrobacterium tumefaciens, a cis-active 24-base-pair sequence adjacent to the right border of the T-DNA, called overdrive, stimulates tumour formation by increasing the level of T-DNA processing. It is thought that the virC operon which enhances T-DNA processing probably does so because the VirC1 protein interacts with overdrive. It has now been shown that the virC1 gene product binds to overdrive but not to the right border of T-DNA [1].

1: The Agrobacterium tumefaciens virC1 gene product binds to overdrive, a T-DNA transfer enhancer. Toro N, Datta A, Carmi OA, Young C, Prusti RK, Nester EW; J Bacteriol 1989;171:6845-6849. PMID:2592351