Allshire lab paper featured in Molecular Cell. Authors Pidoux AL, Choi ES, Abbott JK, Liu X, Kagansky A, Castillo AG, Hamilton GL, Richardson W, Rappsilber J, He X, Allshire RC. Molecular Cell 2009 Feb 13;33(3):299-311. Image Sim1/scm3 mutants have reduced levels of CENP-ACnp1 at centromeres. Wild-type and sim1/scm3 mutants were fixed and stained for Cnp1 (CENP-A), and a spindle pole body (SPB) protein (which indicates the approximate position of the centromeres), and DAPI to stain the DNA. Wild-type cells show a distinctive dot of CENP-ACnp1 staining at centromeres which is severely reduced in sim1/scm3 mutants. Summary CENP-A is a histone H3 variant that is found exclusively at centromeres and forms the foundation of the kinetochore which interacts with spindle microtubules to ensure accurate segregation of chromosomes at mitosis. Major questions in centromere research are how is CENP-A specifically targeted to the centromere and what factors are responsible for its safe delivery. In a screen for fission yeast mutants defective in sub-kinetochore chromatin, the Allshire Lab identified sim1 mutants and found that they have severely reduced CENP-ACnp1 levels at centromeres. The sequence of sim1+ reveals that it encodes a homologue of the budding yeast Scm3 centromere protein. Fission yeast Scm3/Sim1 is a centromere protein that associates with CENP-ACnp1, suggesting that it may act as a receptor and/or assembly factor for CENP-ACnp1 and could thus be an important factor in the epigenetic maintenance of centromere identity. Related links DOI Journal link This article was published on 2024-06-17
