The centromeric sister chromatid cohesion site directs Mcd1p binding to adjacent sequences

Cohesion between sister chromatids occurs along the length of chromosomes, where it plays essential roles in chromosome segregation. We show here that the centromere, a cia-acting cohesion factor, directs the binding of Mcd1p, a cohesin subunit, to at least 2 kb regions flanking centromeres in a sequence-independent manner. The centromere is essential for the maintenance as well as the establishment of this cohesin domain. The efficiency of Mcd1p binding within the cohesin domain is independent of the primary nucleotide sequence of the centromere-flanking DNA but correlates with high A+T DNA content. Thus, the function of centromeres in the cohesion of centromere-proximal regions may be analogous to that of enhancers, nucleating cohesin complex binding over an extended chromosomal domain of A+T-rich DNA.