The Dawe LabThe Dawe Lab

Kinetochores

Anaphase I showing chromosomes in blue, spindle in green, and MIS12 in red.

The lab was founded with the goal of understanding plant kinetochores. We have made good progress by combining the power of maize cytogenetics with high resolution microscopy. Much of our effort has focused on the inner and middle linker regions of kinetochores, and on five key proteins: Centromeric Histone H3 (CENH3), Centromere Protein C (CENP-C), MIS12 (Minichromosome Instability 12), NDC80 (Nuclear Division Cycle 80), and MAD2 (Mitotic Arrest Defective 2). Of particular interest are CENH3 and CENPC, which are the only known DNA binding proteins in plant kinetochores (shown in green in the cartoon at right). Indeed the DNA sequence of centromeres has only a minor role in determining where kinetochores are located, and we believe that CENH3 and CENPC act in concert to give centromeres their identities. To test our ideas we make heavy use of chromatin immunoprecipitation, immunolocalization, and mutant analysis.

 

Our goal is to develop a model for how these proteins are organized, and to identify the set of proteins that are sufficient to organize functional kinetochores. Our most recent strategies involve protein tethering technologies and specialized arrayed binding sites. We are also working on Arabidopsis, taking advantage of its rapid life cycle and tissue specific RNAi methods.