Genome-wide RNAi selection identifies a regulator of transmission stage-enriched gene families and cell-type differentiation in Trypanosoma brucei.
Trypanosoma brucei, causing African sleeping-sickness, exploits quorum-sensing (QS) to generate the 'stumpy forms' necessary for the parasite's transmission to tsetse-flies. These quiescent cells are generated by differentiation in the bloodstream from proliferative slender forms. Using genome-wide RNAi selection we screened for repressors of transmission stage-enriched mRNAs in slender forms, using the stumpy-elevated ESAG9 transcript as a model. This identified REG9.1, whose RNAi-silencing alleviated ESAG9 repression in slender forms and tsetse-midgut procyclic forms. Interestingly, trypanosome surface protein Family 5 and Family 7 mRNAs were also elevated, which, like ESAG9, are T. brucei specific and stumpy-enriched. We suggest these contribute to the distinct transmission biology and vector tropism of T. brucei from other African trypanosome species. As well as surface family regulation, REG9.1-depletion generated QS-independent development to stumpy forms in vivo, whereas REG9.1 overexpression in bloodstream forms potentiated spontaneous differentiation to procyclic forms in the absence of an external signal. Combined, this identifies REG9.1 as a regulator of developmental cell fate, controlling the expression of Trypanosoma brucei-specific molecules elevated during transmission.
Centre for Immunity, Infection and Evolution, Institute for Immunology and Infection Research, School of Biological Sciences, University of Edinburgh, Edinburgh, Scotland, United Kingdom.
Eva
E
Rico
Centre for Immunity, Infection and Evolution, Institute for Immunology and Infection Research, School of Biological Sciences, University of Edinburgh, Edinburgh, Scotland, United Kingdom.
Alasdair
A
Ivens
The Wellcome Trust Centre for Anti-Infectives Research, School of Life Sciences, University of Dundee, Dundee, Scotland, United Kingdom.
Lucy
0000-0001-7191-6890
L
Glover
The Wellcome Trust Centre for Anti-Infectives Research, School of Life Sciences, University of Dundee, Dundee, Scotland, United Kingdom.
David
0000-0001-5173-9284
D
Horn
Centre for Immunity, Infection and Evolution, Institute for Immunology and Infection Research, School of Biological Sciences, University of Edinburgh, Edinburgh, Scotland, United Kingdom.
Keith R
0000-0003-0309-9184
KR
Matthews
D000818:Animals; D002454:Cell Differentiation / Q000235:genetics; D004195:Disease Models, Animal; D005260:Female; D005434:Flow Cytometry; D005786:Gene Expression Regulation / Q000235:genetics*; D055106:Genome-Wide Association Study; D015151:Immunoblotting; D051379:Mice; D015800:Protozoan Proteins / Q000096:biosynthesis* / Q000235:genetics; D034622:RNA Interference; D016601:RNA-Binding Proteins / Q000096:biosynthesis* / Q000235:genetics; D014162:Transfection; D014346:Trypanosoma brucei brucei; D014348:Trypanosoma congolense; D016689:Trypanosoma vivax; D014353:Trypanosomiasis, African / Q000235:genetics* / Q000635:transmission*
D015800:Protozoan Proteins; D016601:RNA-Binding Proteins