title: Evolutionary insights into the role of the essential centromere protein CAL1 in Drosophila.
abstract: Centromeres are essential cis-elements on chromosomes that are crucial for the stable transmission of genetic information during mitotic and meiotic cell divisions. Different species employ a variety of centromere configurations, from small genetically defined centromeres in budding yeast to holocentric centromeres that occupy entire chromosomes in Caenorhabditis, yet the incorporation of nucleosomes containing the essential centromere-specific histone H3 variant CENP-A is a common feature of centromeres in all eukaryotes. In vertebrates and fungi, CENP-A is specifically deposited at centromeres by a conserved chaperone, called HJURP or Scm3, respectively. Surprisingly, homologs of these proteins have not been identified in Drosophila, Caenorhabditis, or plants. How CENP-A is targeted to centromeres in these organisms is not known. The Drosophila centromeric protein CAL1, found only in the Diptera genus, is essential for CENP-A localization, is recruited to centromeres at a similar time as CENP-A, and interacts with CENP-A in both chromatin and pre-nucleosomal complexes, making it a strong candidate for a CENP-A chaperone in this lineage. Here, we discuss the conservation and evolution of this essential centromere factor and report the identification of a "Scm3-domain"-like region with similarity to the corresponding region of fungal Scm3 as well as a shared predicted alpha-helical structure. Given the lack of common ancestry between Scm3 and CAL1, we propose that an optimal CENP-A binding region was independently acquired by CAL1, which caused the loss of an ancestral Scm3 protein from the Diptera lineage.
authors: Department of Molecular and Cell Biology, University of Connecticut, 354 Mansfield Road, U2131, R247, Storrs, CT 06269, USA.
authors: Ragini
authors: R
authors: Phansalkar
authors: Pascal
authors: P
authors: Lapierre
authors: Barbara G
authors: BG
authors: Mellone
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites; D000076247:Centromere Protein A; D042002:Chromatin Assembly and Disassembly; D002868:Chromosomal Proteins, Non-Histone / Q000378:metabolism; D003062:Codon; D004268:DNA-Binding Proteins / Q000378:metabolism*; D004330:Drosophila / Q000378:metabolism*; D029721:Drosophila Proteins / Q000378:metabolism*; D019143:Evolution, Molecular; D006657:Histones / Q000378:metabolism*; D008957:Models, Genetic; D008969:Molecular Sequence Data; D010802:Phylogeny; D017433:Protein Structure, Secondary; D012441:Saccharomyces cerevisiae / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000378:metabolism; D012641:Selection, Genetic; D017386:Sequence Homology, Amino Acid; D013045:Species Specificity
chemical_list: C558282:Cal1 protein, Drosophila; D000076247:Centromere Protein A; D002868:Chromosomal Proteins, Non-Histone; C427237:Cid protein, Drosophila; D003062:Codon; D004268:DNA-Binding Proteins; D029721:Drosophila Proteins; D006657:Histones; D029701:Saccharomyces cerevisiae Proteins; C521684:Scm3 protein, S cerevisiae