Scheme for the development of the pLL-EHC vector containing a centromeric DNA fragment for use as the backbone in AC constructs. (A) Structure of the pLL-EH vector. A 6,212-bp fragment between Pci I and Sal I was isolated from BAC vector pBeloBAC11. (B) Rice BAC clone 38J12 derived from the centromere of chromosome 8 . (C) Ligation of Fse I-digested pLL-EH and BAC 38J12 resulting in the vector pLL-EHC.