A major surface glycoprotein of trypanosoma brucei is expressed transiently during development and can be regulated post-transcriptionally by glycerol or hypoxia

• Published in: Genes & development Vol. 14; no. 5; pp. 615 - 626
• Main Authors: Vassella, E, Den Abbeele, J V, Bütikofer, P, Renggli, C K, Furger, A, Brun, R, Roditi, I
• Format: Journal Article
• Language: English
• Published: United States Cold Spring Harbor Laboratory Press 01.03.2000
• Subjects: AEP protein; Anaerobiosis; Animals; Cell Cycle; Digestive System - parasitology; EP protein; Gene Expression Regulation, Developmental - drug effects; glycerol; Glycerol - pharmacology; Glycoproteins - genetics; GPEET protein; Membrane Glycoproteins - genetics; Protozoan Proteins; Research Paper; Transcription, Genetic; Transfection; Trypanosoma brucei; Trypanosoma brucei brucei - genetics; Trypanosoma brucei brucei - growth & development; Tsetse Flies - parasitology
• ISSN: 0890-9369; 1549-5477
• DOI: 10.1101/gad.14.5.615

Differentiation is a means by which unicellular parasites adapt to different environments. In some cases, the developmental program may be modulated by interactions with the host, but the mechanisms are largely unknown. Trypanosoma brucei is transmitted between mammals by tsetse flies. The development of the procyclic form in the tsetse midgut is marked by the synthesis of a new glycoprotein coat, composed of EP and GPEET procyclins, that is important for survival. Here we demonstrate that the composition of the coat changes in response to extracellular signals in vitro and during development in vivo. EP and GPEET are coinduced when differentiation is initiated. Subsequently, EP expression is maintained, whereas GPEET is repressed after 7-9 days. The timepoint at which GPEET is repressed coincides with the appearance of parasites in a new compartment of the fly midgut. In culture, down-regulation of GPEET can be prevented by exogenous glycerol or accelerated by hypoxia. Regulation is post-transcriptional, and is conferred by the GPEET 3' untranslated region. The same sequence also regulates expression of a reporter gene in the fly. The finding that GPEET is expressed during a defined window during the establishment of infection suggests that it has a specific function in host-parasite interactions rather than a generalized role in shielding underlying membrane molecules.