title: The PARP promoter of Trypanosoma brucei is developmentally regulated in a chromosomal context.
abstract: African trypanosomes are extracellular protozoan parasites that are transmitted from one mammalian host to the next by tsetse flies. Bloodstream forms express variant surface glycoprotein (VSG); the tsetse fly (procyclic) forms express instead the procyclic acidic repetitive protein (PARP). PARP mRNA is abundant in procyclic forms and almost undetectable in blood-stream forms. Post-transcriptional mechanisms are mainly responsible for PARP mRNA regulation but results of nuclear run-on experiments suggested that transcription might also be regulated. We measured the activity of genomically-integrated PARP, VSG and rRNA promoters in permanently-transformed blood-stream and procyclic form trypanosomes, using reporter gene constructs that showed no post-transcriptional regulation. When the constructs were integrated in the rRNA non-transcribed spacer, the ribosomal RNA and VSG promoters were not developmentally regulated, but integration at the PARP locus reduced rRNA promoter activity in bloodstream forms. PARP promoter activity was 5-fold down-regulated in bloodstream forms when integrated at either site. Regulation was probably at the level of transcriptional initiation, but elongation through plasmid vector sequences was also reduced.
authors.affiliation: Zentrum für Molekulare Biologie, Universität Heidelberg, Germany.
authors.forename: S
authors.initials: S
authors.lastname: Biebinger
authors.forename: S
authors.initials: S
authors.lastname: Rettenmaier
authors.forename: J
authors.initials: J
authors.lastname: Flaspohler
authors.forename: C
authors.initials: C
authors.lastname: Hartmann
authors.forename: J
authors.initials: J
authors.lastname: Peña-Diaz
authors.forename: L E
authors.initials: LE
authors.lastname: Wirtz
authors.forename: H R
authors.initials: HR
authors.lastname: Hotz
authors.forename: J D
authors.initials: JD
authors.lastname: Barry
authors.forename: C
authors.initials: C
authors.lastname: Clayton
mesh_terms: D000818:Animals; D001483:Base Sequence; D017931:DNA Primers / Q000737:chemistry; D018507:Gene Expression Regulation, Developmental; D008562:Membrane Glycoproteins / Q000235:genetics*; D008969:Molecular Sequence Data; D011401:Promoter Regions, Genetic; D015800:Protozoan Proteins; D012335:RNA, Ribosomal / Q000235:genetics; D014158:Transcription, Genetic; D014346:Trypanosoma brucei brucei / Q000235:genetics*; D014404:Tubulin / Q000235:genetics
chemical_list: D017931:DNA Primers; D008562:Membrane Glycoproteins; D015800:Protozoan Proteins; D012335:RNA, Ribosomal; D014404:Tubulin; C053277:procyclic acidic repetitive protein, Trypanosoma