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

Nathan Ellis, Maria Proytcheva, Maureen M. Sanz, Tian Zhang Ye, James German

Research output: Contribution to journalArticle

39 Citations (Scopus)

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.

Original languageEnglish (US)
Pages (from-to)1368-1374
Number of pages7
JournalAmerican Journal of Human Genetics
Volume65
Issue number5
DOIs
StatePublished - 1999
Externally publishedYes

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Bloom Syndrome
Sister Chromatid Exchange
Transfection
Fibroblasts
Nuclear Proteins
Complementary DNA
Clone Cells
Western Blotting
Phenotype
Genomic Instability
Human Herpesvirus 4
Fluorescence Microscopy
Chromosomes

ASJC Scopus subject areas

  • Genetics

Cite this

Transfection of BLM into cultured Bloom syndrome cells reduces the sister-chromatid exchange rate toward normal. / Ellis, Nathan; Proytcheva, Maria; Sanz, Maureen M.; Ye, Tian Zhang; German, James.

In: American Journal of Human Genetics, Vol. 65, No. 5, 1999, p. 1368-1374.

Research output: Contribution to journalArticle

Ellis, Nathan ; Proytcheva, Maria ; Sanz, Maureen M. ; Ye, Tian Zhang ; German, James. / Transfection of BLM into cultured Bloom syndrome cells reduces the sister-chromatid exchange rate toward normal. In: American Journal of Human Genetics. 1999 ; Vol. 65, No. 5. pp. 1368-1374.
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