title: The ribose 5-phosphate isomerase-encoding gene is located immediately downstream from that encoding murine immunoglobulin kappa.
abstract: The immunoglobulin kappa locus (Ig kappa) is active only in the B-lymphocyte cell lineage. By exon-trapping we found a gene situated downstream from the murine Ig kappa locus. This gene encodes a protein with 53% sequence identity to the ribose 5-phosphate isomerase A (RPI-A) of Escherichia coli and is therefore likely to be the murine homologue (mRPI) of this enzyme. We confirmed this assumption by showing that a glutathione S-transferase (GST)::mRPI fusion protein has enzymatic activity and that an anti-mRPI antibody detects a protein of the predicted mass of RPI (33 kDa). Cloning and sequencing of the human counterpart show that the RPI gene is evolutionarily conserved. The expression of mRPI is not influenced by the rearrangement status of the Ig kappa locus in B cells and mRPI is expressed in all tissues. We thus show that two genes with very different expression patterns, a housekeeping gene and a gene expressed in a tissue-specific manner, can be located on a chromosome in close proximity to each other.
authors.affiliation: Max-Planck-Institut für Immunobiologie, Freiburg, Germany.
authors.forename: T W
authors.initials: TW
authors.lastname: Apel
authors.forename: A
authors.initials: A
authors.lastname: Scherer
authors.forename: T
authors.initials: T
authors.lastname: Adachi
authors.forename: D
authors.initials: D
authors.lastname: Auch
authors.forename: M
authors.initials: M
authors.lastname: Ayane
authors.forename: M
authors.initials: M
authors.lastname: Reth
mesh_terms: D019747:Aldose-Ketose Isomerases; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D005075:Biological Evolution; D002238:Carbohydrate Epimerases / Q000235:genetics*; D002874:Chromosome Mapping; D017124:Conserved Sequence; D018076:DNA, Complementary / Q000235:genetics; D005091:Exons / Q000235:genetics; D015870:Gene Expression; D005803:Genes, Immunoglobulin / Q000235:genetics*; D015698:Genomic Library; D007145:Immunoglobulin kappa-Chains / Q000235:genetics*; D051379:Mice; D008807:Mice, Inbred BALB C; D008969:Molecular Sequence Data; D012267:Ribosemonophosphates; D017386:Sequence Homology, Amino Acid; D012689:Sequence Homology, Nucleic Acid; D014018:Tissue Distribution
chemical_list: D018076:DNA, Complementary; D007145:Immunoglobulin kappa-Chains; D012267:Ribosemonophosphates; C031626:ribose-5-phosphate; D002238:Carbohydrate Epimerases; D019747:Aldose-Ketose Isomerases; C022548:ribosephosphate isomerase