CENH3 interacts with the centromeric retrotransposon cereba and GC-rich satellites and locates to centromeric substructures in barley
The chromosomal location of centromere-specific histone H3 (CENH3) is the assembly site for the kinetochore complex of active centromeres. Chromatin immunoprecipitation data indicated that CENH3 interacts in barley with cereba, a centromeric retroelement (CR)-like element conserved among cereal centromeres and barley-specific GC-rich centromeric satellite sequences. Anti-CENH3 signals on extended chromatin fibers always colocalized with the centromeric sequences but did not encompass the entire area covered by such centromeric repeats. This indicates that the CENH3 protein is bound only to a fraction of the centromeric repeats. At mitotic metaphase, CENH3, histone H3, and serine 10 phosphorylated histone H3 predominated within distinct structural subdomains of the centromere, as demonstrated by immunogold labeling for high resolution scanning electron microscopy.
KeywordsChromatin Fiber Sister Chromatid Cohesion Centromeric Chromatin Primary Constriction Subtelomeric Repeat
The anti-OsCENH3 antibody was kindly provided by Drs. P. Talbert and S. Henikoff (Howard Hughes Medical Institute, USA) and the anti-histone H3 antibody was kindly provided by Dr. D. Demidov (IPK Gatersleben, Germany). We thank Ingo Schubert (IPK, Germany) for critical reading of the manuscript. AH was supported by a visiting fellowship of the Kyoto University (Japan). The authors gratefully acknowledge Katrin Kumke and Sabine Steiner for excellent technical assistance.
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