Isolation and characterization of a mammalian homolog of the Drosophila white gene

Gene. 1997 Jan 31;185(1):77-85. doi: 10.1016/s0378-1119(96)00633-6.


The Drosophila melanogaster white gene is a member of the ABC transporter superfamily of ATPase transmembrane proteins and is involved in the cellular uptake of guanine and tryptophan. We have cloned and sequenced human and mouse homologs of white which share 55-58% amino acid similarity with the Drosophila protein. Northern analysis reveals that the mammalian homolog is highly expressed in several tissues, including brain, spleen, lung and placenta. We have localized the gene to human chromosome 21q22.3 by means of fluorescence in situ hybridization and linkage analysis using a (CA)n polymorphism. The human homolog maps to the interval between D21S212 and D21S171, a region which includes loci for bipolar affective disorder and a recessive form of deafness. Since tryptophan is a precursor for the neurotransmitter serotonin and neurotoxic metabolites of the kynurenine pathway, we propose that the human homolog of white is a suitable candidate gene for these neurological disorders in humans.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • ATP-Binding Cassette Transporters / genetics*
  • Amino Acid Sequence
  • Animals
  • Blotting, Northern
  • Brain / metabolism
  • Chromosome Mapping
  • Chromosomes, Human, Pair 21
  • Cloning, Molecular
  • DNA, Complementary / genetics
  • Drosophila melanogaster / genetics
  • Fibroblasts
  • Gene Expression Regulation
  • Genetic Linkage
  • Humans
  • In Situ Hybridization
  • Lung / metabolism
  • Mice
  • Molecular Sequence Data
  • Placenta / metabolism
  • Polymorphism, Genetic
  • RNA / analysis
  • Sequence Alignment
  • Sequence Homology, Amino Acid
  • Spleen / metabolism


  • ATP-Binding Cassette Transporters
  • DNA, Complementary
  • RNA

Associated data

  • GENBANK/U34919
  • GENBANK/U34920