Fig 1.
The life cycle of Trypanosoma congolense.
Passage of T. congolense through the tsetse fly host. Colors represent different parasite developmental stages within distinct tsetse tissues. Tsetse ingests bloodstream-form T. congolense (1), which migrate to the fly’s midgut and differentiate into procyclic forms (2). Procyclic parasites then cross tsetse’s peritrophic matrix and move anteriorly through the ectoperitrophic space to the cardia where they again differentiate into long trypomastigotes (3). Finally, trypomastigotes colonize the PB (thecal bulb, labrum and hypopharynx) and differentiate into the epimastigote and then metacyclic forms (4), the latter of which are inoculated into a vertebrate host during a subsequent feed (5).
Fig 2.
Functional classification of PB-enriched genes based on gene ontology (GO).
Genes preferentially expressed in the tsetse fly proboscis were analyzed using Blast2GO gene ontology tool. The terms were categorized into biological processes, molecular function and cellular processes. The number of genes assigned to each term in different categories are indicated in brackets.
Fig 3.
Differential expression and gene ontology (GO) analysis of genes exhibiting increased and decreased expression during trypanosome infection.
(A) Differentially expressed genes between T. congolense infected PB and uninfected PB of tsetse fly. (B) Significantly enriched pathways determined through ProfCom [51]. * Differentially expressed dataset ** Entire Drosophila genes in ProfCom database. The ticks in both the Y and X axis are positioned in a Log10 scale.
Fig 4.
Heat maps representation of differentially expressed transcripts in different functional categories (A-G). Heat maps obtained by plotting the normalized expression profiles (RPKM, Log2 transformed) of individual transcripts in uninfected and infected conditions in the R-package software. The heat maps (dendrograms) were clustered using euclidean distance calculation and ward.D clustering methods. The clusters were then manually separated to various functional categories.
Table 1.
Tsetse immunity transcripts differentially expressed between infected-PB compared to uninfected PB.
Fig 5.
Summary of specific differentially expressed protein encoding genes that contain transmembrane and/or signal-peptide domains in the proboscis.
(A) Read abundance and fold difference in gene expression. Genes in red are PB-enriched while those in blue are from the complete PB transcriptome. (B-D) Fold change (based on RPKM differences) in expression of protein encoding genes that contain transmembrane (TM; B), signal peptide (SP; C) or both TM and SP domains (D) in T. congolense infected proboscis. This analysis is based on RNA-seq data from PB-enriched and complete PB transcriptome datasets and contain only genes whose combined RPKM and number of TM domains is at least 1000 and 3 respectively for TM proteins and a combine RPKM of at least 500 for SP.