title: Identification and characterization of novel variant major surface glycoprotein gene families in rat Pneumocystis carinii.
abstract: The major surface glycoprotein (MSG) is an abundant, immunodominant protein on the surface of the opportunistic pathogen Pneumocystis carinii. The current study identified two novel variant MSG (vMSG) gene families in rat P. carinii that are closely related to but distinct from MSG. These gene families encode proteins of approximately 90 kDa (v1MSG) and approximately 115 kDa (v2MSG). Compared with MSG, v1MSG is characterized by a deletion near the carboxyl terminus. The predicted v1MSG and v2MSG proteins are highly homologous to MSG at the carboxyl, but not the amino, terminus. Like MSG, they are cysteine-rich. Approximately 10% of the apparent molecular weight is due to N-linked glycosylation. Southern blotting studies demonstrated that, like MSG, v1MSG and v2MSG are the products of multicopy gene families. However, unlike MSG, each vMSG gene encodes a signal peptide, suggesting that the regulation of vMSG is different from that of MSG.
authors.affiliation: Critical Care Medicine Department, Clinical Center, National Institutes of Health, Bethesda, Maryland, USA.
authors.forename: S N
authors.initials: SN
authors.lastname: Huang
authors.forename: C W
authors.initials: CW
authors.lastname: Angus
authors.forename: R E
authors.initials: RE
authors.lastname: Turner
authors.forename: V
authors.initials: V
authors.lastname: Sorial
authors.forename: J A
authors.initials: JA
authors.lastname: Kovacs
mesh_terms: D020121:5' Untranslated Regions; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D018076:DNA, Complementary / Q000235:genetics; D004271:DNA, Fungal / Q000235:genetics; D005656:Fungal Proteins / Q000737:chemistry / Q000235:genetics*; D015966:Gene Expression Regulation, Fungal; D005800:Genes, Fungal; D014644:Genetic Variation; D006031:Glycosylation; D008562:Membrane Glycoproteins / Q000737:chemistry / Q000235:genetics*; D008969:Molecular Sequence Data; D008970:Molecular Weight; D005810:Multigene Family; D015345:Oligonucleotide Probes / Q000235:genetics; D011010:Pneumocystis / Q000235:genetics*; D021382:Protein Sorting Signals / Q000737:chemistry / Q000235:genetics; D051381:Rats; D017386:Sequence Homology, Amino Acid; D012689:Sequence Homology, Nucleic Acid
chemical_list: D020121:5' Untranslated Regions; D018076:DNA, Complementary; D004271:DNA, Fungal; D005656:Fungal Proteins; D008562:Membrane Glycoproteins; D015345:Oligonucleotide Probes; D021382:Protein Sorting Signals; C077556:GPA protein, Pneumocystis carinii sp.