An Investigation into the Protein Composition of the Teneral Glossina morsitans morsitans Peritrophic Matrix

Abstract

BackgroundTsetse 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), which is 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 trypanosomes do so is not understood. In order to better comprehend the molecular events surrounding trypanosome penetration 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.MethodsPMs from male teneral (young, unfed) flies were dissected, solubilised in urea/SDS buffer and the proteins precipitated with cold acetone/TCA. The PM proteins were either subjected to an in-solution tryptic digestion or fractionated on 1D SDS-PAGE, and the resulting bands digested using trypsin. The tryptic fragments from both preparations were purified and analysed by LC-MS/MS.ResultsOverall, nearly 300 proteins were identified from both analyses, several of those containing signature Chitin Binding Domains (CBD), including novel peritrophins and peritrophin-like glycoproteins, which are essential in maintaining PM architecture and may act as trypanosome adhesins. Furthermore, 27 proteins from the tsetse secondary endosymbiont, Sodalis glossinidius, were also identified, suggesting this bacterium is probably in close association with the tsetse PM.ConclusionTo our knowledge this is the first report on the protein composition of teneral 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 and may help identify potential molecular targets to block trypanosome development within the tsetse.

The Peritrophic Matrix Mediates Differential Infection Outcomes in the Tsetse Fly Gut following Challenge with Commensal, Pathogenic, and Parasitic Microbes

“…These genes were chosen because they are an integral component of PM formation processes in other insects ( CS ; 26, 27). Additionally, P1 and P2 are highly expressed in tsetse’s cardia, and Pro1 and Pro2 are proteinaceous components of the fly’s PM (28, 29). In an effort to achieve potent knock down of target gene expression, we employed a robust RNAi-based protocol that included feeding and injecting target dsRNAs into distinct groups of tsetse.…”

Mammalian African trypanosome VSG coat enhances tsetse’s vector competence

“…In particular, we noted a reduction in cardia-specific transcripts (pro1, pro2, pro3, and per12) that encode the major PM-associated Peritrophins. Peritrophins are structural PM proteins that bind chitin fibers and influence elasticity or porosity of the PM (15,25). In addition to Peritrophins, we also surveyed for changes in expression of additional PM constituents that were identified through proteomic analysis of PM dissected from teneral adult guts (15) and noted a reduction in serine protease 6, serine endopeptidase, and hsp60.…”

Genome Sequence of the Tsetse Fly ( Glossina morsitans ): Vector of African Trypanosomiasis

“…This proteomic data identified the corresponding genes in the Glossina genome. Three of these genes are exclusively expressed by the proventriculus (table S6) (11). …”

“…( Bottom ) Glossina digestive physiology and the infection process by trypanosomes. Associated satellite references for these findings are listed within the figure as numbers in parentheses and correspond to the reference list (8, 11, 12). …”

“…Associated text describes significant findings regarding the Glossina microbiome and the associated impacts in terms of Glossina immunity, nutrition, vectorial capacity, and vector control. Associated satellite references are listed within the figure as numbers in parentheses and correspond to the reference list (11, 13). …”