title: Characterization of a relatively rare class B, type 2 trypanosome variant surface glycoprotein gene.
abstract: The variant surface glycoprotein (VSG) gene of Trypanosoma brucei rhodesiense LouTat 1.5, a defined African trypanosome variant antigenic type, was cloned and sequenced. Southern blot analysis revealed 2 DNA restriction fragments in both VSG 1.5 expressor and nonexpressor populations, suggesting that there are 2 genomic copies of the VSG 1.5 gene and no expression-linked copies. Pulsed-field gel electrophoresis followed by Southern blot analysis showed that each copy of the VSG 1.5 gene exists on a separate large chromosome in both the expressor (approximately 3.5- and 4-megabase (Mb) chromosomes) and nonexpressor (approximately 4- and 5.7-Mb chromosomes) populations. Thus, VSG genes may be present on larger chromosomes than previously reported. Sequence analysis and alignments revealed that the VSG 1.5 molecule is a class B VSG with 12 cysteine residues in the N-terminus and is classified as a type 2 VSG based on C-terminus motifs. This classification shows that the VSG 1.5 molecule represents a relatively rare VSG class and type. Taken together, these studies provide additional information on VSG genes and proteins and supply the foundation for structure-function analysis of the VSG 1.5 surface antigen expressed by trypanosomes of the LouTat 1 serodeme.
authors.affiliation: University of Wisconsin-Madison, Department of Bacteriology, 53705, USA.
authors.forename: L R
authors.initials: LR
authors.lastname: Schopf
authors.forename: J M
authors.initials: JM
authors.lastname: Mansfield
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D015152:Blotting, Northern; D015139:Blotting, Southern; D004262:DNA Restriction Enzymes; D016054:DNA, Protozoan / Q000032:analysis*; D016521:Electrophoresis, Gel, Pulsed-Field; D051379:Mice; D008969:Molecular Sequence Data; D016053:RNA, Protozoan / Q000032:analysis; D013045:Species Specificity; D016833:Trypanosoma brucei rhodesiense / Q000235:genetics*; D014643:Variant Surface Glycoproteins, Trypanosoma / Q000737:chemistry / Q000235:genetics*
chemical_list: D016054:DNA, Protozoan; D016053:RNA, Protozoan; D014643:Variant Surface Glycoproteins, Trypanosoma; D004262:DNA Restriction Enzymes