title: A promotor directing alpha-amanitin-sensitive transcription of GARP, the major surface antigen of insect stage Trypanosoma congolense.
abstract: The major surface antigen of procyclic and epimastigote forms of Trypanosoma congolense in the tsetse fly is GARP (glutamic acid/alanine-rich protein), which is thought to be the analogue of procyclin/PARP in Trypanosoma brucei. We have studied two T.congolense GARP loci (the 4.3 and 4.4 loci) whose transcription is alpha-amanitin sensitive. Whilst a transcriptional gap 5' of the first GARP gene in the cloned region of the 4.4 locus could not be detected, such a gap was present in the 5' flank of the first GARP gene in the 4.3 locus. We have located a GARP transcription start site and, using reporter gene constructs containing a putative GARP promoter region in transient transfection studies, we have demonstrated promoter activity for the test region in T.congolense. There are species-specific differences in sequences regulating expression of the two major surface antigens, GARP and procyclin/PARP: the GARP promoter is inactive in T.brucei while the procyclin/PARP promoter is inactive in T.congolense. We have defined the splice acceptor site for the 4.3 GARP gene by sequencing and by 5' RT-PCR and demonstrated microheterogeneity in GARP polyadenylation by 3' RT-PCR. It appears that some GARP and procyclin/PARP RNA processing signals, although similar, are also species-specific.
authors.affiliation: Wellcome Unit of Molecular Parasitology, The Anderson College, University of Glasgow, UK.
authors.forename: S V
authors.initials: SV
authors.lastname: Graham
authors.forename: D
authors.initials: D
authors.lastname: Jefferies
authors.forename: J D
authors.initials: JD
authors.lastname: Barry
mesh_terms: D000546:Amanitins / Q000494:pharmacology*; D000818:Animals; D000953:Antigens, Protozoan / Q000235:genetics; D001483:Base Sequence; D005786:Gene Expression Regulation; D017125:Genes, Protozoan / Q000235:genetics; D008562:Membrane Glycoproteins / Q000235:genetics*; D008969:Molecular Sequence Data; D011401:Promoter Regions, Genetic / Q000235:genetics*; D015800:Protozoan Proteins / Q000235:genetics*; D012323:RNA Processing, Post-Transcriptional / Q000235:genetics; D012326:RNA Splicing / Q000235:genetics; D012333:RNA, Messenger / Q000032:analysis / Q000378:metabolism; D016053:RNA, Protozoan / Q000032:analysis / Q000378:metabolism; D013045:Species Specificity; D014158:Transcription, Genetic / Q000187:drug effects*; D014346:Trypanosoma brucei brucei / Q000235:genetics; D014348:Trypanosoma congolense / Q000235:genetics* / Q000276:immunology
chemical_list: D000546:Amanitins; D000953:Antigens, Protozoan; C406724:GARP protein, Trypanosoma; D008562:Membrane Glycoproteins; D015800:Protozoan Proteins; D012333:RNA, Messenger; D016053:RNA, Protozoan; C053277:procyclic acidic repetitive protein, Trypanosoma