Characterization of the Genomic Xist Locus in Rodents Reveals Conservation of Overall Gene Structure and Tandem Repeats but Rapid Evolution of Unique Sequence

  1. Tatyana B. Nesterova1,2,3,
  2. Sergey Ya. Slobodyanyuk1,
  3. Eugene A. Elisaphenko1,
  4. Alexander I. Shevchenko1,
  5. Colette Johnston2,
  6. Marina E. Pavlova1,
  7. Igor B. Rogozin1,
  8. Nikolay N. Kolesnikov1,
  9. Neil Brockdorff2, and
  10. Suren M. Zakian1
  1. 1Institute of Cytology and Genetics, Russian Academy of Sciences, Siberian Department, Novosibirsk 630090, Russia; 2MRC Clinical Sciences Centre, Imperial College School of Medicine, Hammersmith Hospital, London W12 ONN, UK

Abstract

The Xist locus plays a central role in the regulation of X chromosome inactivation in mammals, although its exact mode of action remains to be elucidated. Evolutionary studies are important in identifying conserved genomic regions and defining their possible function. Here we report cloning, sequence analysis, and detailed characterization of the Xist gene from four closely related species of common vole (field mouse), Microtus arvalis. Our analysis reveals that there is overall conservation of Xistgene structure both between different vole species and relative to mouse and human Xist/XIST. Within transcribed sequence, there is significant conservation over five short regions of unique sequence and also over Xist-specific tandem repeats. The majority of unique sequences, however, are evolving at an unexpectedly high rate. This is also evident from analysis of flanking sequences, which reveals a very high rate of rearrangement and invasion of dispersed repeats. We discuss these results in the context of Xist gene function and evolution.

[The sequence data described in this paper have been submitted to the GenBank data library under accession nos.AJ310127AJ310130 and AJ311670.]

Footnotes

  • 3 Corresponding author.

  • E-MAIL tatyana.nesterova{at}csc.mrc.ac.uk; FAX 44-(0)-208-383-8303.

  • Article and publication are at www.genome.org/cgi/doi/10.1101/gr.174901.

    • Received December 11, 2000.
    • Accepted February 27, 2001.
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