title: CENP-B is a highly conserved mammalian centromere protein with homology to the helix-loop-helix family of proteins.
abstract: CENP-B is a centromere associated protein originally identified in human cells as an 80 kDa autoantigen recognized by sera from patients with anti-centromere antibodies (ACA). Recent evidence indicates that CENP-B interacts with centromeric heterochromatin in human chromosomes and may bind to a specific subset of human alphoid satellite DNA. CENP-B has not been unambiguously identified in non-primates and could, in principal, be a primate-specific alphoid DNA binding protein. In this work, a human genomic DNA segment containing the CENP-B gene was isolated and subjected to DNA sequence analysis. In vitro expression identified the site for translation initiation of CENP-B, demonstrating that it is encoded by an intronless open reading frame (ORF) in human DNA. A homologous mouse gene was also isolated and characterized. It was found to possess a high degree of homology with the human gene, containing an intronless ORF coding for a 599 residue polypeptide with 96% sequence similarity to human CENP-B. 5' and 3' flanking and untranslated sequences were conserved at a level of 94.6% and 82.7%, respectively, suggesting that the regulatory properties of CENP-B may be conserved as well. CENP-B mRNA was detected in mouse cells and tissues and an immunoreactive nuclear protein identical in size to human CENP-B was detected in mouse 3T3 cells using human ACA. Analysis of the sequence of CENP-B revealed a segment of significant similarity to a DNA binding motif identified for the helix-loop-helix (HLH) family of DNA binding proteins. These data demonstrate that CENP-B is a highly conserved mammalian protein that may be a member of the HLH protein family and suggest that it plays a role in a conserved aspect of centromere structure or function.
authors.affiliation: Department of Molecular Biology, Research Institute of Scripps Clinic, La Jolla, CA 92037.
authors.forename: K F
authors.initials: KF
authors.lastname: Sullivan
authors.forename: C A
authors.initials: CA
authors.lastname: Glass
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001324:Autoantigens / Q000235:genetics* / Q000302:isolation & purification; D001483:Base Sequence; D002503:Centromere / Q000737:chemistry*; D051936:Centromere Protein B; D002868:Chromosomal Proteins, Non-Histone / Q000235:genetics* / Q000302:isolation & purification; D003001:Cloning, Molecular; D004268:DNA-Binding Proteins; D005796:Genes; D006367:HeLa Cells; D006801:Humans; D008214:Lymphocytes / Q000737:chemistry; D051379:Mice; D008969:Molecular Sequence Data; D011487:Protein Conformation; D012689:Sequence Homology, Nucleic Acid; D013045:Species Specificity; D013329:Structure-Activity Relationship
chemical_list: D001324:Autoantigens; C497926:CENPB protein, human; C497927:Cenpb protein, mouse; D051936:Centromere Protein B; D002868:Chromosomal Proteins, Non-Histone; D004268:DNA-Binding Proteins