title: Episomal expression of specific sense and antisense mRNAs in Leishmania amazonensis: modulation of gp63 level in promastigotes and their infection of macrophages in vitro.
abstract: The major surface glycoprotein (gp63) of Leishmania amazonensis is a metalloprotease implicated in the infection of mammalian macrophages. The expression of gp63 and its participation in this infection were further examined by modulating the level of this molecule in a virulent gp63-abundant wild-type clone. Promastigotes were transfected with gp63 genes cloned into a Leishmania-specific vector in two different orientations, leading to the expression of gp63 sense and antisense RNAs. With increasing selective pressure, cell surface gp63 was increasingly augmented in the transfectants with sense transcripts and suppressed to a very low level in those with antisense transcripts. Thus, the expression of gp63 from chromosomal, repetitive genes is not stringently regulated at the protein level and can be substantially reduced by episomal antisense transcription of a single copy. The transfectants differed significantly only in the level of gp63, thereby allowing specific evaluation of this molecule in leishmanial infection of macrophages in vitro. Kinetic studies of infection in vitro indicate that gp63 plays a role not only in the binding of this parasite to these macrophages but also in its intramacrophage survival and replication.
authors.affiliation: Department of Microbiology/Immunology, University of Health Sciences/Chicago Medical School, North Chicago, Illinois 60064, USA.
authors.forename: D Q
authors.initials: DQ
authors.lastname: Chen
authors.forename: B K
authors.initials: BK
authors.lastname: Kolli
authors.forename: N
authors.initials: N
authors.lastname: Yadava
authors.forename: H G
authors.initials: HG
authors.lastname: Lu
authors.forename: A
authors.initials: A
authors.lastname: Gilman-Sachs
authors.forename: D A
authors.initials: DA
authors.lastname: Peterson
authors.forename: K P
authors.initials: KP
authors.lastname: Chang
mesh_terms: D000818:Animals; D001483:Base Sequence; D066298:In Vitro Techniques; D007894:Leishmania mexicana / Q000201:enzymology* / Q000235:genetics* / Q000472:pathogenicity; D008264:Macrophages / Q000469:parasitology; D008666:Metalloendopeptidases / Q000235:genetics* / Q000378:metabolism*; D051379:Mice; D015345:Oligonucleotide Probes / Q000235:genetics; D010957:Plasmids / Q000235:genetics; D016372:RNA, Antisense / Q000235:genetics; D012333:RNA, Messenger / Q000235:genetics*; D016053:RNA, Protozoan / Q000235:genetics*; D014158:Transcription, Genetic; D014162:Transfection; D014774:Virulence
chemical_list: D015345:Oligonucleotide Probes; D016372:RNA, Antisense; D012333:RNA, Messenger; D016053:RNA, Protozoan; D008666:Metalloendopeptidases; C055146:glycoprotein gp63, Leishmania