Molecular basis for decreased folylpoly-γ-glutamate synthetase expression in a methotrexate resistant CCRF-CEM mutant cell line

Guy J. Leclerc, Teresa A. York, Tingting Hsieh-Kinser, Julio C. Barredo

Research output: Contribution to journalArticle

12 Scopus citations


A CCRF-CEM mutant, CEM-p, has been shown to exhibit resistance to methotrexate due to decreased methotrexate polyglutamate accumulation. To ascertain the mechanism(s) responsible for this phenotype, we analyzed FPGS and SLC19A1 mRNA expression, examined FPGS promoter activity, and determined nucleotide sequence of the FPGS promoter and full length cDNA from CCRF-CEM and CEM-p cells. We identified in FPGS from CEM-p cells three amino acid substitutions that altered the ATP binding P-loop, glutamate/folate binding, and a conserved domain located at the carboxyl-terminal. Our data demonstrated for the first time the importance of the highly conserved domain (VTGSLHLVGGV) located at the carboxyl-terminal for FPGS activity.

Original languageEnglish (US)
Pages (from-to)293-299
Number of pages7
JournalLeukemia Research
Issue number3
StatePublished - Mar 1 2007



  • Folate
  • FPGS
  • Leukemia
  • Methotrexate resistance
  • Mutagenesis
  • Mutant
  • Point mutation
  • SLC19A1
  • T-ALL

ASJC Scopus subject areas

  • Cancer Research
  • Hematology
  • Oncology

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