Dr. Black's laboratory is interested in how particular proteins direct accurate chromosome segregation at mitosis. In humans, the chromosomal element—the centromere—that directs this process is not defined by a particular DNA sequence. Rather, the location of the centromere is dictated by an epigenetic mark generated by one or more resident proteins. These centromeric proteins interact directly with the DNA to create a specialized chromatin compartment that is distinct from any other part of the chromosome. By taking biophysical, biochemical, and cell biological approaches, our work is to define the composition and physical characteristics of the protein and protein/DNA complexes that epigenetically mark the location of the centromere on the chromosome. This work involves building centromeric chromatin from its component parts for analysis of its physical characteristics, developing biochemical assays to reconstitute steps in the process of establishing and maintaining the epigenetic mark, and using cell-based approaches to study the behavior of proteins involved in centromere inheritance and other essential aspects related to chromosome segregation at cell division.