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Dysfunction of chromosomal loop attachment sites: illegitimate recombination linked to matrix association regions and

A O Sperry1, V C Blasquez, W T Garrard

  • 1Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas 75235.

Proceedings of the National Academy of Sciences of the United States of America
|July 1, 1989
PubMed

Insights

Matrix association regions (MARs) bind and are cleaved by topoisomerase II. MAR dysfunction may cause illegitimate recombination, a type of DNA rearrangement observed in gene studies and chromosomal abnormalities.

Area of Science:

  • Genetics
  • Molecular Biology
  • Chromosomal Structure

Background:

  • Matrix association regions (MARs) are A + T-rich sequences involved in chromosomal loop attachment.
  • Topoisomerase II is a key protein in the mitotic chromosomal scaffold.

Purpose of the Study:

  • To investigate the interaction between MARs and topoisomerase II.
  • To explore the role of MARs in illegitimate recombination.

Main Methods:

  • Binding assays to assess MARs' interaction with topoisomerase II.
  • Analysis of MARs in specific gene loci and chromosomal abnormalities.
  • Comparison with known mechanisms of illegitimate recombination.

Main Results:

  • MARs specifically bind and are cleaved by topoisomerase II.
  • Topoisomerase II cutting hotspots are found in MARs at translocation breakpoints.
  • MAR deletion and association with repetitive elements at recombination junctions were observed.

Conclusions:

  • MARs are direct targets of topoisomerase II.
  • MAR dysfunction is proposed as a mechanism for illegitimate recombination in eukaryotes.

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