title: A procyclin-associated gene in Trypanosoma brucei encodes a polypeptide related to ESAG 6 and 7 proteins.
abstract: The procyclin genes of Trypanosoma brucei encode a family of glycoproteins expressed on the surface of procyclic forms of the parasite. These genes are present at different loci in tandem arrays of two or three copies depending on the strain. It has previously been shown that procyclin genes are transcribed from a promotor immediately upstream of the first procyclin gene in each cluster by an RNA polymerase that is resistant to high levels of alpha-amanitin. Here we show that additional genes, which we term procyclin-associated genes (PAGs), are located downstream of the procyclin genes and belong to the same alpha-amanitin-resistant polycistronic transcription units. A gene in the pro A locus, PAG 1, encodes a polypeptide that is related to the ESAG 6 and 7 proteins encoded in the VSG expression site. An unexpected feature of PAG 1 is that the major open reading frame of 405 amino acids only starts at position 1283 in the cDNA sequence and extends to the poly(A) tail. Sequences related to the 5' untranslated region of PAG 1 are also found downstream of procyclin genes in other loci, but the 3' coding region is unique to Pro A. This suggests that there are related PAGs which are coordinately transcribed with procyclin genes from different loci.
authors.affiliation: Kernforschungszentrum Karlsruhe, Institut für Genetik und Toxikologie, FRG.
authors.forename: E
authors.initials: E
authors.lastname: Koenig-Martin
authors.forename: M
authors.initials: M
authors.lastname: Yamage
authors.forename: I
authors.initials: I
authors.lastname: Roditi
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D015152:Blotting, Northern; D015139:Blotting, Southern; D003001:Cloning, Molecular; D016054:DNA, Protozoan / Q000737:chemistry; D005091:Exons; D017125:Genes, Protozoan; D006023:Glycoproteins; D008562:Membrane Glycoproteins; D008969:Molecular Sequence Data; D009693:Nucleic Acid Hybridization; D016366:Open Reading Frames; D016133:Polymerase Chain Reaction; D015800:Protozoan Proteins / Q000737:chemistry / Q000235:genetics*; D015183:Restriction Mapping; D017422:Sequence Analysis, DNA; D014158:Transcription, Genetic; D014346:Trypanosoma brucei brucei / Q000235:genetics*; D014643:Variant Surface Glycoproteins, Trypanosoma / Q000235:genetics*
chemical_list: D016054:DNA, Protozoan; D006023:Glycoproteins; D008562:Membrane Glycoproteins; D015800:Protozoan Proteins; D014643:Variant Surface Glycoproteins, Trypanosoma; C053277:procyclic acidic repetitive protein, Trypanosoma; C078011:ESAG 7 protein, Trypanosoma brucei