title: A developmentally regulated gene of trypanosomes encodes a homologue of rat protein-disulfide isomerase and phosphoinositol-phospholipase C.
abstract: We have isolated and characterized a developmentally regulated gene in Trypanosoma brucei, arbitrarily termed BS2. BS2 mRNA is substantially more abundant in bloodstream-form trypanosomes than in procyclic culture forms. Its nucleotide sequence reveals a single contiguous open-reading frame of 497 codons and is predicted to encode a protein of approximately 55.5 kilodaltons. A search of the NBRF protein data base revealed that within the predicted amino acid sequence are two of the evolutionarily conserved redox sites typified by thioredoxin of bacteria. Of this family of proteins, the recently sequenced rat genes encoding protein-disulfide isomerase (PDI) and form I phosphoinositide-specific phospholipase C (PIPLC) showed homology extending over the length of all three proteins (i.e., between BS2, PDI, and PIPLC). Although this homology includes the acidic C-terminus characteristic of proteins localized to the lumen of the endoplasmic reticulum, the BS2 product is predicted to possess multiple sites for N-linked glycosylation while PDI and PIPLC have none. Possible roles of the BS2 gene product in trypanosome physiology are discussed.
authors.affiliation: Department of Microbiology and Immunology, Stanford University School of Medicine, California 94305-5402.
authors.forename: M P
authors.initials: MP
authors.lastname: Hsu
authors.forename: M L
authors.initials: ML
authors.lastname: Muhich
authors.forename: J C
authors.initials: JC
authors.lastname: Boothroyd
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D003001:Cloning, Molecular; D005796:Genes; D005809:Genes, Regulator; D007535:Isomerases / Q000235:genetics*; D008969:Molecular Sequence Data; D009693:Nucleic Acid Hybridization; D043265:Phosphatidylinositol Diacylglycerol-Lyase; D010727:Phosphoric Diester Hydrolases / Q000235:genetics*; D019704:Protein Disulfide-Isomerases; D051381:Rats; D015183:Restriction Mapping; D012689:Sequence Homology, Nucleic Acid; D012984:Software; D013045:Species Specificity; D014346:Trypanosoma brucei brucei / Q000201:enzymology / Q000235:genetics* / Q000254:growth & development
chemical_list: D010727:Phosphoric Diester Hydrolases; D043265:Phosphatidylinositol Diacylglycerol-Lyase; D007535:Isomerases; D019704:Protein Disulfide-Isomerases