Transfection of BLM into cultured Bloom syndrome cells reduces the sister-chromatid exchange rate toward normal Journal Article


Authors: Ellis, N. A.; Proytcheva, M.; Sanz, M. M.; Ye, T. Z.; German, J.
Article Title: Transfection of BLM into cultured Bloom syndrome cells reduces the sister-chromatid exchange rate toward normal
Abstract: The gene BLM, mutated in Bloom syndrome (BS), encodes the nuclear protein BLM, which when absent, as it is from most BS cells, results in genomic instability. A manifestation of this instability is an excessive rate of sister-chromatid exchange (SCE). Here we describe the effects on this abnormal cellular phenotype of stable transfection of normal BLM cDNAs into two types of BS cells, SV40-transformed fibroblasts and Epstein-Barr virus (EBV)-transformed lymphoblastoid cells. Clones of BLM-transfected fibroblasts produced normal amounts of BLM by western blot analysis and displayed a normal nuclear localization of the protein by immunofluorescence microscopy. They had a mean of 24 SCEs/46 chromosomes, in contrast to the mean of 69 SCEs in controls transfected only with the vector. BLM-transfected fibroblast clones that expressed highest levels of the BLM protein had lowest levels of SCE. The lymphoblastoid cells transfected with BLM had SCE frequencies of 22 and 42 in two separate experiments in which two different selectable markers were used, in contrast to 57 and 58 in vector-transfected cells; in this type cell, however, the BLM protein was below the level detectable by western blot analysis. These experiments prove that BLM cDNA encodes a functional protein capable of restoring to or toward normal the uniquely characteristic high-SCE phenotype of BS cells.
Keywords: controlled study; human cell; mutation; protein localization; cells, cultured; nuclear protein; transfection; nuclear proteins; blotting, western; fluorescent antibody technique; molecular sequence data; genetic transfection; nucleotide sequence; simian virus 40; fibroblasts; sister chromatid exchange; lymphocytes; adenosine triphosphatases; dna helicases; fibroblast culture; herpesvirus 4, human; immunofluorescence microscopy; human herpesvirus 4; transformation, genetic; bloom syndrome; humans; human; priority journal; article
Journal Title: American Journal of Human Genetics
Volume: 65
Issue: 5
ISSN: 0002-9297
Publisher: Cell Press  
Date Published: 1999-11-01
Start Page: 1368
End Page: 1374
Language: English
DOI: 10.1086/302616
PUBMED: 10521302
PROVIDER: scopus
PMCID: PMC1288289
DOI/URL:
Notes: Article -- Export Date: 16 August 2016 -- Source: Scopus
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  1. Nathan A Ellis
    74 Ellis
  2. Tian Z Ye
    14 Ye