DNA binding of centromere protein C (CENPC) is stabilized by single-stranded RNA

• Published in: PLoS genetics 2010-02, Vol.6 (2), p.e1000835
• Main Authors: Du, Yaqing, Topp, Christopher N, Dawe, R Kelly
• Format: Article
• Language: English
• Subjects: Base Sequence; Cell Biology/Nuclear Structure and Function; Cell Biology/Plant Cell Biology; Centromeres; Chromatin - metabolism; Chromosomal Proteins, Non-Histone - genetics; Chromosomal Proteins, Non-Histone - metabolism; Deoxyribonucleic acid; DNA; DNA, Plant - metabolism; DNA-ligand interactions; Epigenetics; Exons - genetics; Gene Expression Regulation, Plant; Genetic research; Genetics; Genetics and Genomics/Chromosome Biology; Kinetochores - metabolism; Methods; Models, Biological; Nucleotide sequence; Observations; Plant Proteins - genetics; Plant Proteins - metabolism; Properties; Protein Binding; Protein C; Proteins; Recombinant Fusion Proteins - metabolism; RNA, Messenger - genetics; RNA, Messenger - metabolism; RNA, Plant - metabolism; Sequence Deletion; Transcription, Genetic; Zea mays - genetics; Zea mays - metabolism
• ISSN: 1553-7404; 1553-7390; 1553-7404
• DOI: 10.1371/journal.pgen.1000835

Centromeres are the attachment points between the genome and the cytoskeleton: centromeres bind to kinetochores, which in turn bind to spindles and move chromosomes. Paradoxically, the DNA sequence of centromeres has little or no role in perpetuating kinetochores. As such they are striking examples of genetic information being transmitted in a manner that is independent of DNA sequence (epigenetically). It has been found that RNA transcribed from centromeres remains bound within the kinetochore region, and this local population of RNA is thought to be part of the epigenetic marking system. Here we carried out a genetic and biochemical study of maize CENPC, a key inner kinetochore protein. We show that DNA binding is conferred by a localized region 122 amino acids long, and that the DNA-binding reaction is exquisitely sensitive to single-stranded RNA. Long, single-stranded nucleic acids strongly promote the binding of CENPC to DNA, and the types of RNAs that stabilize DNA binding match in size and character the RNAs present on kinetochores in vivo. Removal or replacement of the binding module with HIV integrase binding domain causes a partial delocalization of CENPC in vivo. The data suggest that centromeric RNA helps to recruit CENPC to the inner kinetochore by altering its DNA binding characteristics.