Successful passage of cellular generation requires the replication of the chromosomes and their segregation into new daughter cells. Centromeres are the chromosomal sites that direct chromosome segregation.
Our lab is focused on understanding the molecular organization of centromeric chromatin. Centromeres are unusual in that the functional identity of the locus is not determined by DNA, but by the proteins associated with them. Examination of the assembly of a chromatin complex comprised of proteins CENP-T/W/S/X has identified a distinctive chromatin assembly pathway active after DNA replication that is required for kinetochore formation. (Fig 1).
Efforts are currently focused on mapping centromeric chromatin using a novel equine cell system developed by collaborator Elena Giulotto at the University of Pavia. Analysis of Equus asinus, the domestic donkey, has identified a set of centromeres that are formed on unique genomic DNA sequence rather than repetitive satellite DNA. These centromeres open an avenue for application of ChIP-Seq methods for dissection of chromatin structure. (Figure 2) We are currently investigating the nucleosomal organization of the centromere and identifying the location of inner centromere components. The long range goal of these experiments is to establish a high resolution molecular map of the centromeric chromatin fiber and its critical components under different physiological conditions in the cell cycle.