Project description:Background: Tsetse flies serve as biological vectors for several species of African trypanosomes. In order to survive, proliferate and establish a midgut infection, trypanosomes must cross the tsetse fly peritrophic matrix (PM), an acellular gut lining surrounding the blood meal. Crossing of this multi layered structure occurs at least twice during parasite migration and development, but the mechanism of how they do so is poorly understood. In order to better comprehend the molecular events surrounding trypanosome crossing of the tsetse PM, a mass spectrometry-based approach was applied to investigate the PM protein composition using Glossina morsitans morsitans as a model organism. Methods: Urea-SDS extracts of tsetse PM proteins were either subject to an in solution tryptic digestion or fractionated on 1D SDS-PAGE and the resulting bands digested with trypsin. The tryptic fragments from both preparations were purified and analysed by 2D-LC-MS/MS. Tandem MS data were searched against the Glossina-morsitans-Yale_PEPTIDES_GmorY1.1 database downloaded from VectorBase (https://www.vectorbase.org/proteomes) using the Mascot (version 2.3.02, Matrix Science) search engine. Search parameters were a precursor mass tolerance of 10 ppm for the in-solution digest using the LTQ-Orbitrap Velos and 0.6 Da for the lower resolution LTQ instrument. Fragment mass tolerance was 0.6 Da for both instruments. One missed cleavage was permitted, carbamidomethylation was set as a fixed modification and oxidation (M) was included as a variable modification. For in-solution data, the false discovery rate was <1%, and individual ion scores >30 were considered to indicate identity or extensive homology (p <0.05 ). Results: Overall, over 200 proteins were identified, several of those containing Chitin Binding Domains (CBD), a signature of insect PM proteins, including novel peritrophins and peritrophin-like glycoproteins, which are essential in maintaining PM architecture and may act as trypanosome adhesins. Furthermore, a minimum of 27 proteins were also identified from the tsetse secondary endosymbiont, Sodalis glossinidius, suggesting this bacterium is probably in close association with the tsetse PM. Conclusion: To our knowledge this is the first report on the protein composition of G. m. morsitans, an important vector of African trypanosomes. Further functional analyses of these proteins will lead to a better understanding of the tsetse physiology as well as to identification of potential targets to block trypanosome development within the tsetse.
Project description:Transmission of Trypanosoma brucei by tsetse flies involves the deposition of the infective quiescent metacyclic stage into the mammalian skin at the site of the fly’s bite. In the skin, the metacyclic parasites reactivate and differentiate into proliferative trypanosomes before colonizing the host's blood and tissues. We have generated an advanced human skin equivalent and used tsetse flies to naturally infect the artificial skin with trypanosomes. We have detailed the chronological order of the parasites' development in the skin and found a rapid activation and differentiation of the tsetse-transmitted cell cycle‑arrested metacyclic trypanosomes to proliferative parasites. Single-parasite transcriptomics documented the biological events during differentiation and host invasion at five different time points. After the establishment of a proliferative trypanosome population in the skin, the parasites entered a reversible quiescence program characterized by slow replication and a strongly reduced metabolism. We termed these quiescent trypanosomes skin tissue forms (STF), which may play an important role in maintaining the trypanosome infection in aparasitemic, asymptomatic individuals.
Project description:How flagellar signaling regulates the host interaction of parasites remains a challenge due to poor conservation of signaling systems with those in cilia of higher organisms. The trypanosome-specific cAMP response protein 3 (CARP3) shows developmentally regulated localization at the flagellar tip membrane, where it is essential for parasite swarming and colonization of the tsetse fly insect vector. This project describes a proximity-dependent proteomics approach (BioID) that identified proteins in close vicinity of CARP3 in the bloodstream stage of Trypanosoma brucei.
Project description:How flagellar signaling regulates the host interaction of parasites remains a challenge due to poor conservation of signaling systems with those in cilia of higher organisms. The trypanosome-specific cAMP response protein 3 (CARP3) shows developmentally regulated localization at the flagellar tip membrane, where it is essential for parasite swarming and colonization of the tsetse fly insect vector. This project describes a label-free, quantitative proteomics approach that identifies proteins changing in abundance upon inducible CARP3 knock down in bloodstream stage Trypanosoma brucei.
Project description:The gene expression of Trypanosoma brucei has been examined extensively in the blood of mammalian hosts and in forms found in the midgut of its arthropod vector, the tsetse fly. However, trypanosomes also undergo development within the mammalian bloodstream as they progress from morphologically M-bM-^@M-^Xslender formsM-bM-^@M-^Y to transmissible M-bM-^@M-^Xstumpy formsM-bM-^@M-^Y through morphological intermediates. This transition is temporally progressive within the first wave of parasitaemia such that gene expression can be monitored in relatively pure slender and stumpy populations as well as during the progression between these extremes. The development also represents the progression of cells from translationally active forms adapted for proliferation in the host to translationally quiescent forms, adapted for transmission. We have used metabolic labelling to quantitate translational activity in slender forms, stumpy forms and in forms undergoing early differentiation to procyclic forms in vitro. Thereafter we have examined the cohort of total mRNAs that are enriched in throughout development in the mammalian bloodstream (slender, intermediate and stumpy forms), irrespective of strain, revealing those that exhibit consistent developmental regulation rather than sample specific changes. Transcripts that cosediment with polysomes in stumpy forms and slender forms have also been identified to enrich transcripts that escape translational repression prior to transmission. Combined, the expression and polysomal association of transcripts as trypanosomes undergo development in the mammalian bloodstream haves been defined, providing a resource for trypanosome researchers. This facilitates the identification of those that undergo developmental regulation in the bloodstream and therefore those likely to have a role in the survival and capacity for transmission of stumpy forms. Examination of gene expression during life cycle stages.
Project description:How flagellar signaling regulates the host interaction of parasites remains a challenge due to poor conservation of signaling systems with those in cilia of higher organisms. The trypanosome-specific cAMP response protein 3 (CARP3) shows developmentally regulated localization at the flagellar tip membrane, where it is essential for parasite swarming and colonization of the tsetse fly insect vector. This project describes identification of CARP3-YFP interacting proteins by GFP trap pull down followed by mass spectrometry in the bloodstream stage as well as in the procyclic stage of Trypanosoma brucei.
2022-08-31 | PXD025398 | Pride
Project description:Antennal molecular responses in tsetse fly to blood feeding
Project description:The African trypanosome Trypanosoma brucei is a unicellular eukaryote, which relies on a protective Variant Surface Glycoprotein (VSG) coat for survival in the mammalian host. A single trypanosome has >2000 VSG genes and pseudogenes of which only one is expressed from one of ~15 telomeric bloodstream form expression sites (BESs). Infectious metacyclic trypanosomes present within the tsetse fly vector also express VSG from a separate set of telomeric metacyclic ESs (MESs). All MESs are silenced in bloodstream form T. brucei. As very little is known about how this is mediated, we performed a whole genome RNAi library screen to identify MES repressors. This allowed us to identify a novel SAP domain containing DNA binding protein which we called TbSAP. TbSAP is enriched at the nuclear periphery and binds both MESs and BESs. Knockdown of TbSAP in bloodstream form trypanosomes did not result in cells becoming more ‘metacyclic’-like. Instead, there was extensive global upregulation of transcripts including MES VSGs, VSGs within the silent VSG arrays as well as genes immediately downstream of BES promoters. TbSAP therefore appears to be a novel architectural chromatin protein playing an important role in silencing the extensive VSG repertoire of bloodstream form T. brucei.