Drosophila CENH3 is sufficient for centromere formation
04.11.2011
Mendiburo MJ, Padeken J, Fülöp S, Schepers A, Heun P.
Science. 2011 Nov 4;334(6056):686-90
CENH3 is a centromere-specific histone H3 variant essential for kinetochore assembly. Despite its central role in centromere function, there has been no conclusive evidence supporting CENH3 as sufficient to determine centromere identity. To address this question, we artificially targeted Drosophila CENH3 (CENP-A/CID) as a CID-GFP-LacI fusion protein to stably integrated lac operator
(lacO) arrays. This ectopic CID focus assembles a functional kinetochore and directs incorporation of CID molecules without the LacI-anchor, providing evidence for the self-propagation of the epigenetic mark. CID-GFP-LacI–bound extrachromosomal lacO plasmids can assemble kinetochore proteins and bind microtubules, resulting in their stable transmission for several cell generations even after eliminating CID-GFP-LacI. We conclude that CID is both necessary and sufficient to serve as an epigenetic centromere mark and nucleate heritable centromere function.
A mitotic cell with most chromosomes at the metaphase plate is shown. Centromeres are visualized by antibody staining against CENH3-GFP-LacI
(green) and an outer kinetochore protein (NDC80; red). DNA is shown in blue. The arrowhead points to minichromosomes with induced
neocentromeres