title: VSG 117 gene is conservatively present and early expressed in Trypanosma evansi YNB stock.
abstract: African trypanosomes, including Trypanosoma brucei and the closely related species Trypanosoma evansi, are flagellated unicellular parasites that proliferate extracellularly in the mammalian bloodstream and tissue spaces. They evade host immune system by periodically switching their variant surface glycoprotein (VSG) coat. Each trypanosome possesses a vast archive of VSGs with distinct sequence identity and different strains contain different archive of VSGs. VSG 117 was reported as a widespread VSG detected in the genomes of all the T. brucei strains. In this study, the presence and expression of VSG 117 gene was observed in T. evansi YNB stock by RT-PCR with VSG-specific primers. We further confirmed that this VSG tends to be expressed in the early stage of T. evansi infections (on day 12-15) by immuno-screening the previously isolated infected blood samples. It is possible that the VSG 117 gene evolved and spread through the African trypanosome population via genetic exchange, before T. evansi lost its ability to infect tsetse fly. Our finding provided an evidence of the close evolutionary relationship between T. evansi and T. brucei, in the terms of VSG genes.
authors.affiliation: National Animal Protozoa Laboratory & College of Veterinary Medicine, China Agricultural University, Beijing 100193, China. jarregon@163.com
authors.forename: Yonggen
authors.initials: Y
authors.lastname: Jia
authors.forename: Liang
authors.initials: L
authors.lastname: Guo
authors.forename: Xinxin
authors.initials: X
authors.lastname: Zhao
authors.forename: Xun
authors.initials: X
authors.lastname: Suo
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D005075:Biological Evolution; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000737:chemistry; D016054:DNA, Protozoan / Q000737:chemistry; D005260:Female; D005786:Gene Expression Regulation; D051379:Mice; D008969:Molecular Sequence Data; D017354:Point Mutation; D011817:Rabbits; D016415:Sequence Alignment; D014345:Trypanosoma / Q000145:classification / Q000235:genetics* / Q000276:immunology; D014346:Trypanosoma brucei brucei / Q000145:classification / Q000235:genetics / Q000276:immunology; D014353:Trypanosomiasis, African / Q000469:parasitology*; D014643:Variant Surface Glycoproteins, Trypanosoma / Q000737:chemistry / Q000235:genetics*
chemical_list: D018076:DNA, Complementary; D016054:DNA, Protozoan; D014643:Variant Surface Glycoproteins, Trypanosoma