Oct 23, 2012

The Neurospora crassa chr-1 gene is up-regulated by chromate and its encoded CHR-1 protein causes chromate sensitivity and chromium accumulation

Current Genetics
Luis J Flores-AlvarezFélix Gutiérrez-Corona

Abstract

The ChrA membrane protein belongs to the CHR superfamily of chromate ion transporters, which includes homologues from bacteria, archaea and eukaryotes. Bacterial ChrA homologues confer chromate resistance by exporting chromate ions from the cell's cytoplasm. The Neurospora crassa strain 74-A chr-1 gene encodes a putative CHR-1 protein of 507 amino acid residues, which belongs to the CHR superfamily. RT-PCR assays showed that expression of the chr-1 gene was up-regulated by chromate exposure of N. crassa cultures. Introduction in N. crassa of sense and antisense fragments of the chr-1 gene, as part of a silencing module within the pSilent-1 vector, produced transformants with a phenotype of resistance to chromate and diminished accumulation of chromium, as compared with the control strain containing only the vector. A chromate-resistance phenotype was also observed in N crassa strains deleted in the genomic chr-1 gene, thus confirming that the absence of CHR-1 protein confers chromate resistance to the fungus. The cDNA from N. crassa chr-1 gene (Ncchr-1) was cloned into the pYES2 vector under the control of a GAL promoter and the resulting recombinant plasmid was transferred to the yeast Saccharomyces cerevisiae. Galactose-induc...Continue Reading

  • References21
  • Citations3

References

  • References21
  • Citations3

Citations

Mentioned in this Paper

Chromium product (pharmacologic preparation)
Neurospora crassa
Transformation, Genetic
Shuttle Vectors
Galactose Measurement
Genome
Saccharomyces cerevisiae allergenic extract
Conidia
Promoter
Gene Expression Regulation, Fungal

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