title: Variation in the major surface glycoprotein genes in Pneumocystis jirovecii.
abstract: The genome of Pneumocystis, which causes life-threatening pneumonia in immunosuppressed patients, contains a multicopy gene family that encodes the major surface glycoprotein (Msg). Pneumocystis can vary the expressed Msg, presumably as a mechanism to avoid host immune responses. Analysis of 24 msg-gene sequences obtained from a single human isolate of Pneumocystis demonstrated that the sequences segregate into 2 branches. Results of a number of analyses suggest that recombination between msg genes is an important mechanism for generating msg diversity. Intrabranch recombination occurred more frequently than interbranch recombination. Restriction-fragment length polymorphism analysis of human isolates of Pneumocystis demonstrated substantial variation in the repertoire of the msg-gene family, variation that was not observed in laboratory isolates of Pneumocystis in rats or mice; this may be the result of examining outbred versus captive populations. Increased diversity in the Msg repertoire, generated in part by recombination, increases the potential for antigenic variation in this abundant surface protein.
authors.affiliation: Critical Care Medicine Department, National Institutes of Health Clinical Center, National Institutes of Health, Bethesda, Maryland, USA.
authors.forename: Geetha
authors.initials: G
authors.lastname: Kutty
authors.forename: Frank
authors.initials: F
authors.lastname: Maldarelli
authors.forename: Guillaume
authors.initials: G
authors.lastname: Achaz
authors.forename: Joseph A
authors.initials: JA
authors.lastname: Kovacs
mesh_terms: D000818:Animals; D001483:Base Sequence; D004271:DNA, Fungal / Q000235:genetics; D005656:Fungal Proteins / Q000235:genetics* / Q000378:metabolism; D015966:Gene Expression Regulation, Fungal; D014644:Genetic Variation; D006801:Humans; D008562:Membrane Glycoproteins / Q000235:genetics* / Q000378:metabolism; D051379:Mice; D016513:Mice, SCID; D008969:Molecular Sequence Data; D010802:Phylogeny; D045363:Pneumocystis carinii / Q000235:genetics* / Q000378:metabolism; D051381:Rats
chemical_list: D004271:DNA, Fungal; D005656:Fungal Proteins; D008562:Membrane Glycoproteins; C077556:GPA protein, Pneumocystis carinii sp.