Open AccessFormation of functional centromeric chromatin is specified epigenetically in Candida albicans
Author(s) -
Mary Baum,
Kaustuv Sanyal,
Prashant Mishra,
Nathaniel Thaler,
John Carbon
Publication year - 2006
Publication title -
proceedings of the national academy of sciences of the united states of america
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.011
H-Index - 771
eISSN - 1091-6490
pISSN - 0027-8424
DOI - 10.1073/pnas.0606958103
Subject(s) - chromatin , candida albicans , genetics , biology , microbiology and biotechnology , dna
In the pathogenic yeastCandida albicans , the 3-kb centromeric DNA regions (CEN ) of each of the eight chromosomes have different and unique DNA sequences. The centromeric histone CaCse4p (CENP-A homolog) occurs only within these 3-kbCEN regions to form specialized centromeric chromatin. Centromere activity was maintained on small chromosome fragments derivedin vivo by homologous recombination of a native chromosome with linear DNA fragments containing a telomere and a selectable marker. Anin vivo derived 85-kb truncated chromosome containing the 3-kbCEN7 locus on 69 kb of chromosome 7 DNA was stably and autonomously maintained in mitosis, indicating that preexisting activeCEN chromatin remains functional through many generations. This same 85-kb chromosome fragment, isolated as naked DNA (devoid of chromatin proteins) fromC. albicans and reintroduced back intoC. albicans cells by standard DNA transformation techniques, was unable to reform functionalCEN chromatin and was mitotically unstable. Comparison of active and inactiveCEN chromatin digested with micrococcal nuclease revealed that periodic nucleosome arrays are disrupted at active centromeres. Chromatin immunoprecipitation with antibodies against CaCse4p confirmed thatCEN 7 introduced intoC. albicans cells as naked DNA did not recruit CaCse4p or induce its spread to a duplicate region only 7 kb away from activeCEN7 chromatin. These results indicate that CaCse4p recruitment and centromere activation are epigenetically specified and maintained inC. albicans.