Display Settings:

Format

Send to:

Choose Destination
See comment in PubMed Commons below
Proc Natl Acad Sci U S A. 2006 Apr 25;103(17):6706-11. Epub 2006 Apr 14.

Evidence on the chromosomal location of centromeric DNA in Plasmodium falciparum from etoposide-mediated topoisomerase-II cleavage.

Author information

  • 1Department of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT, United Kingdom. john.kelly@lshtm.ac.uk

Abstract

Centromeres are the chromosomal loci that facilitate segregation, and, in most eukaryotes, they encompass extensive regions of genomic DNA. Topoisomerase-II has been identified as a crucial regulator of segregation in a wide range of organisms and exhibits premitotic accumulation at centromeres. Consistent with this property, treatment of cells with the topoisomerase-II inhibitor etoposide promotes chromosomal cleavage at sites within centromeric DNA. In the case of the human malaria parasite Plasmodium falciparum, despite a completed genome sequence, there are no experimental data on the nature of centromeres. To address this issue, we have used etoposide-mediated topoisomerase-II cleavage as a biochemical marker to map centromeric DNA on all 14 parasite chromosomes. We find that topoisomerase-II activity is concentrated at single chromosomal loci and that cleavage sites extend over approximately 10 kb. A shared feature of these topoisomerase-II cleavage sites is the presence of an extremely AT-rich ( approximately 97%) domain with a strictly defined size limit of 2.3-2.5 kb. Repetitive arrays identified within the domains do not display interchromosomal conservation in terms of length, copy number, or sequence. These unusual properties suggest that P. falciparum chromosomes contain a class of "regional" centromere distinct from those described in other eukaryotes, including the human host.

PMID:
16617116
[PubMed - indexed for MEDLINE]
PMCID:
PMC1458945
Free PMC Article

Images from this publication.See all images (6)Free text

Fig. 1.
Fig. 2.
Fig. 3.
Fig. 4.
Fig. 5.
Fig. 6.
PubMed Commons home

PubMed Commons

0 comments
How to join PubMed Commons

    Supplemental Content

    Full text links

    Icon for HighWire Icon for PubMed Central
    Loading ...
    Write to the Help Desk