Evidence for BLM and Topoisomerase IIIα interaction in genomic stability Journal Article


Authors: Hu, P.; Beresten, S. F.; Van Brabant, A.; Ye, T. Z.; Pandolfi, P. P.; Johnson, F. B.; Guarente, L.; Ellis, N. A.
Article Title: Evidence for BLM and Topoisomerase IIIα interaction in genomic stability
Abstract: The genomic instability of persons with Bloom's syndrome (BS) features particularly an increased number of sister-chromatid exchanges (SCEs). The primary cause of the genomic instability is mutation at BLM, which encodes a DNA helicase of the RecQ family. BLM interacts with Topoisomerase IIIα (Topo IIIα), and both BLM and Topo IIIα localize to the nuclear organelles referred to as the promyelocytic leukemia protein (PML) nuclear bodies. In this study we show, by analysis of cells that express various deletion constructs of green fluorescent protein (GFP)-tagged BLM, that the first 133 amino acids of BLM are necessary and sufficient for interaction between Topo IIIα and BLM. The Topo IIIα-interaction domain of BLM is not required for BLM's localization to the PML nuclear bodies; in contrast, Topo IIIα is recruited to the PML nuclear bodies via its interaction with BLM. Expression of a full-length BLM (amino acids 1-1417) in BS cells can correct their high SCEs to normal levels, whereas expression of a BLM fragment that lacks the Topo IIIα interaction domain (amino acids 133-1417) results in intermediate SCE levels. The deficiency of amino acids 133-1417 in the reduction of SCEs was not explained by a defect in DNA helicase activity, because immunoprecipitated 133-1417 protein had 4-fold higher activity than GFP-BLM. The data implicate the BLM-Topo IIIα complex in the regulation of recombination in somatic cells.
Keywords: controlled study; unclassified drug; gene mutation; human cell; gene deletion; clinical feature; protein domain; protein localization; phenotype; cytology; somatic cell; gene expression; nuclear protein; green fluorescent protein; protein interaction; tumor cells, cultured; enzyme activity; hela cells; gene expression regulation; genetic recombination; promyelocytic leukemia; immunoprecipitation; cell line, transformed; sister chromatid exchange; genetic stability; amino acid; protein structure, tertiary; binding sites; helicase; protein family; adenosine triphosphatases; dna helicases; gene location; cell secretion; dna topoisomerase; dna topoisomerases, type i; gene construct; cell nucleus inclusion body; bloom syndrome; humans; human; priority journal; article; blm protein; dna topoisomerase iiialpha; amino acid deficiency
Journal Title: Human Molecular Genetics
Volume: 10
Issue: 12
ISSN: 0964-6906
Publisher: Oxford University Press  
Date Published: 2001-06-01
Start Page: 1287
End Page: 1298
Language: English
PUBMED: 11406610
PROVIDER: scopus
DOI: 10.1093/hmg/10.12.1287
DOI/URL:
Notes: Export Date: 21 May 2015 -- Source: Scopus
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MSK Authors
  1. Peng Hu
    7 Hu
  2. Nathan A Ellis
    74 Ellis
  3. Tian Z Ye
    14 Ye