Budding yeast centromeric DNA and A+T rich bacterial DNA can function as centromeres in the fission yeast Schizosaccharomyces pombe.

Abstract

Eukaryotic centromeric DNA is famously variable in evolution but currently, this cannot be reconciled with the conservation of eukaryotic centromere function. It seems likely that centromeric DNA from different organisms contains conserved functionally important features but the identity of these features is unknown. The point centromeres of the budding yeast Saccharomyces cerevisiae and the regional centromeres of the fission yeast Schizosaccharomyces pombe are separated by 350 million years of evolution and are canonical examples of the paradoxical relationship1 between centromeric DNA sequence and function. We have established a centromere-replacement strategy in Schizosaccharomyces pombe in order to resolve this paradox experimentally. Centromere-replacement shows that an A+T rich bacterial DNA sequence has weak centromere function and that elements of the Saccharomyces cerevisiae centromere embedded in short sequences from the non-centromeric S. pombe wee1 gene function almost as well as native S. pombe centromeric DNA. These observations demonstrate that determinants of centromere function are held in common by the budding and fission yeasts and that A+T rich DNA is both necessary and sufficient for function in S. pombe. Given the evolutionary distance between these yeasts, it is likely that A+T rich DNA has centromere function in a wide variety of eukaryotes. Centromere-replacement uses unidirectional serine recombinases that work well in many organisms2 3 and our experimental strategy should allow this idea to be tested in other eukaryotes.