title: Glycoprotein 46 mRNA abundance is post-transcriptionally regulated during development of Leishmania chagasi promastigotes to an infectious form.
abstract: GP46 is an abundant glycoprotein of 46 kDa on the surface of the promastigote form of most Leishmania species. We show that the steady state level of GP46 mRNA increases >>30-fold as Leishmania chagasi promastigotes develop in vitro from a less infectious form during logarithmic growth to a highly infectious form in the stationary phase of cultivation. Nuclear run-on experiments demonstrate that this increase in GP46 mRNA abundance is regulated post-transcriptionally. Plasmids containing the 3'-untranslated regions (UTRs) and downstream intergenic regions (IRs) of two different GP46 genes fused immediately downstream of the beta-galactosidase coding region were transfected into L. chagasi, and beta-galactosidase activity and mRNA levels were examined. The presence of the 3'-UTR + IR of one GP46 gene (gp46A) resulted in a steady increase in beta-galactosidase activity and mRNA level as the transfected promastigotes developed from logarithmic to stationary phase. This differential effect parallels that of the 3'-UTRs + IRs of a family of genes for an unrelated Leishmania surface glycoprotein, GP63. Thus, post-transcriptional regulation of the genes for two different surface glycoproteins of Leishmania occurs via a similar mechanism.
authors.affiliation: Department of Biochemistry, University of Iowa, Iowa City, Iowa 52242, USA.
authors.forename: J K
authors.initials: JK
authors.lastname: Beetham
authors.forename: K S
authors.initials: KS
authors.lastname: Myung
authors.forename: J J
authors.initials: JJ
authors.lastname: McCoy
authors.forename: M E
authors.initials: ME
authors.lastname: Wilson
authors.forename: J E
authors.initials: JE
authors.lastname: Donelson
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002874:Chromosome Mapping; D018076:DNA, Complementary / Q000302:isolation & purification; D017930:Genes, Reporter; D007891:Leishmania / Q000254:growth & development* / Q000472:pathogenicity; D008562:Membrane Glycoproteins / Q000235:genetics* / Q000378:metabolism; D008969:Molecular Sequence Data; D015800:Protozoan Proteins / Q000235:genetics* / Q000378:metabolism; D012323:RNA Processing, Post-Transcriptional; D012333:RNA, Messenger / Q000378:metabolism*; D016415:Sequence Alignment; D014158:Transcription, Genetic; D014162:Transfection; D001616:beta-Galactosidase / Q000235:genetics
chemical_list: D018076:DNA, Complementary; D008562:Membrane Glycoproteins; D015800:Protozoan Proteins; D012333:RNA, Messenger; C066248:surface glycoprotein GP46-M-2, Leishmania; D001616:beta-Galactosidase