Cytogenetic and molecular evaluation of centromere-associated DNA sequences from a marsupial (Macropodidae:Macropus rufogriseus) X chromosome

Kira Bulazel, Cushla Metcalfe, Gianni C. Ferreri, Jingwei Yu, Mark D B Eldridge, Rachel J. O'Neill*

*Corresponding author for this work

    Research output: Contribution to journalArticlepeer-review

    23 Citations (Scopus)

    Abstract

    The constitution of the centromeric portions of the sex chromosomes of the red-necked wallaby, Macropus rufogriseus (family Macropodidae, subfamily Macropodinae), was investigated to develop an overview of the sequence composition of centromeres in a marsupial genome that harbors large amounts of centric and pericentric heterochromatin. The large, C-band-positive centromeric region of the X chromosome was microdissected and the isolated DNA was microcloned. Further sequence and cytogenetic analyses of three representative clones show that all chromosomes in this species carry a 178-bp satellite sequence containing a CENP-B DNA binding domain (CENP-B box) shown herein to selectively bind marsupial CENP-B protein. Two other repeats isolated in this study localize specifically to the sex chromosomes yet differ in copy number and intrachromosomal distribution. Immunocytohistochemistry assays with anti-CENP-E, anti-CREST, anti-CENP-B, and anti-trimethyl-H3K9 antibodies defined a restricted point localization of the outer kinetochore at the functional centromere within an enlarged pericentric and heterochromatic region. The distribution of these repeated sequences within the karyotype of this species, coupled with the apparent high copy number of these sequences, indicates a capacity for retention of large amounts of centromere-associated DNA in the genome of M. rufogriseus.

    Original languageEnglish
    Pages (from-to)1129-1137
    Number of pages9
    JournalGenetics
    Volume172
    Issue number2
    DOIs
    Publication statusPublished - Feb 2006

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