Cyclins in initiation

M. Wahi and A.D. Johnson have investigated the SRB genes and discovered that the SRB10 and SRB11 are actively involved in the phosphorylation of the II carboxy-terminal domain (CTD). The CTD is phylogenetically conserved and the SRB10 and SRB11 facilitate the conservation process. CTD are sometimes removed by deletion mutations that are lethal to cells. The SRB genes restrict the deletion mutations thereby enhancing the phylogenetic conservation of the CTD.