Expression profiles of tsetse (glossina spp) glossina proteolytic lectin (gpl) gene

Tsetse flies are important agricultural and medical vectors of African trypanosomes, the causative agents of trypanosomosis in humans and animals. The life cycle of the protozoan parasite Trypanosoma, in its invertebrate vector begins when the tsetse fly feeds on an infected mammalian host. An important step in the establishment of tsetse midgut infection involves transformation of bloodstream-form trypanosomes into procyclic forms. This process is mediated by a wide variety of factors, all of which are intrinsic to the tsetse, trypanosome and the host blood. Tsetse midgut factors involved include lectins, trypsin-like molecules, lysins and lectin-trypsin complex. Recently Glossina proteolytic lectin gene (Gp!) that encodes for a protein with both lectin and trypsin activities in Glossina fuscipes fuscipes was discovered. Glossina proteolytic lectin induces transformation of bloodstream-forms trypanosomes to procyclic forms in vitro.The gene is ~loodmeal induced and is expressed in members of Glossina species but not in other haematophagous insects., This suggests that it may be playing an important role in the interactions between tsetse and the trypanosomes and hence the vectorial capacity. The present study was undertaken to gain insight into the effect of trypanosome parasites on the expression of Gpl gene and how its expression compares in different G!ossina _'S."pec.Ies. Quantitative competitive reverse transcriptase polymerase chain reaction (QCRT- PCR) was used to assess the expression levels of Gpl gene in infected and uninfected G·fjilscipes~24, 48 and 72 h post feeding. Expression levels were also compared in G. pallidipes and G. f fuscipes at 0, 24, 48 and 72 h post feeding. Expression levels of Gpl gene remained high throughout th~ digestion cycle following both infective and uninfective bloodmeal. However, the expression was parasite responsive, with the expression being lower in trypanosome infected G j fuscipes (p