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The novel BLM3 gene encodes a protein that protects against lethal effects of oxidative damage

D E Febres1, A Pramanik, M Caton

  • 1Department of Microbiology, City University of New York Medical School and Sophie Davis School of Biomedical Education, New York 10031, USA.

Cellular and Molecular Biology (Noisy-Le-Grand, France)
|February 15, 2002
PubMed

Insights

Mutations in the BLM3 gene cause sensitivity to radiation and cancer drugs like bleomycin. The BLM3 gene

Area of Science:

  • Molecular Biology
  • Genetics
  • Biochemistry

Background:

  • The BLM3 gene in Saccharomyces cerevisiae is implicated in cellular resistance to DNA-damaging agents.
  • Bleomycin, an anticancer drug, shares structural similarities with phleomycin, and both induce hypersensitivity when BLM3 is mutated.
  • Bleomycin is a clinically relevant chemotherapeutic agent used for various cancers.

Purpose of the Study:

  • To clone and characterize the BLM3 gene responsible for drug hypersensitivity.
  • To elucidate the potential function of the Blm3 protein (Blm3p) in cellular protection mechanisms.

Main Methods:

  • Gene cloning by complementation of drug hypersensitivity.
  • Nucleotide sequencing and analysis of the BLM3 gene.
  • Creation of a blm3 null mutation via gene replacement.
  • Northern dot blot analysis to assess BLM3 expression in human tissues.

Main Results:

  • The BLM3 gene was cloned, and its nucleotide sequence predicts an integral membrane protein with multiple transmembrane domains.
  • The blm3 null mutation is not essential for growth under normal conditions but confers hypersensitivity to bleomycin and phleomycin.
  • Sequence analysis suggests Blm3p may belong to the major facilitator superfamily (MFS) of permeases.
  • BLM3 sequence homology was detected in adult human tissues but not in fetal tissues.

Conclusions:

  • The BLM3 gene product, Blm3p, is a potential permease involved in cellular defense mechanisms.
  • Proposed functions for Blm3p include detoxification, transport, and protection against DNA damage from oxidative agents.
  • The differential expression of BLM3 in adult versus fetal tissues suggests a role in specific physiological processes or responses.

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