Sequence divergence among members of a trypanosome variant surface glycoprotein gene family.
We have used analysis of DNA sequence data from four members of a Trypanosoma brucei variant surface glycoprotein gene family to investigate the molecular basis of the generation of antigenic diversity in African trypanosomes. Among these four sequences we find the greatest similarity in the untranslated sequences immediately upstream from the coding region. A complex pattern of nucleic acid and predicted amino acid sequence divergence appears starting at the coding sequence. Two related but highly divergent hydrophobic leaders are associated with different members of this gene family; both forms of these hydrophobic leaders appear to exist in other isolates of T. b. brucei. We find conservative replacements in the first 120 predicted amino acid residues of the mature protein; the following 80 predicted residues show less conservative replacements, and we suggest that this region may be hypervariable and exposed to the aqueous environment.
Beals
T P
TP
Department of Microbiology and Immunology, Stanford University School of Medicine, CA 94305.
Boothroyd
J C
JC
D000595:Amino Acid Sequence; D000818:Animals; D000940:Antigenic Variation; D001483:Base Sequence; D004247:DNA; D016054:DNA, Protozoan / Q000235:genetics* / Q000302:isolation & purification; D008969:Molecular Sequence Data; D005810:Multigene Family; D014176:Protein Biosynthesis; D011487:Protein Conformation; D012333:RNA, Messenger / Q000235:genetics; D015183:Restriction Mapping; D012689:Sequence Homology, Nucleic Acid; D014346:Trypanosoma brucei brucei / Q000235:genetics* / Q000276:immunology; D014643:Variant Surface Glycoproteins, Trypanosoma / Q000235:genetics*
D016054:DNA, Protozoan; D012333:RNA, Messenger; D014643:Variant Surface Glycoproteins, Trypanosoma; D004247:DNA