Size heterogeneity among antigenically related Giardia lamblia variant-specific surface proteins is due to differences in tandem repeat copy number.
Giardia lamblia undergoes antigenic variation by modulating the expression of the different genes that comprise the trophozoite's variant-specific surface protein (VSP) repertoire. We studied an epitope that is conserved among VSPs expressed by cloned trophozoite lines derived from the independent G. lamblia isolates WB, G3M, Be-2, and CAT. The epitope recognized by monoclonal antibody 6E7 lies entirely within the region of tandemly repeated 65-amino-acid units that is characteristic of these size-variant VSPs. Northern (RNA) hybridization, cDNA cloning, and DNA sequence analysis indicate that size heterogeneity among these VSPs is due to differences in the number of repetitive units.
Mowatt
M R
MR
Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, Bethesda, Maryland 20892.
Nguyen
B Y
BY
Conrad
J T
JT
Adam
R D
RD
Nash
T E
TE
D000595:Amino Acid Sequence; D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology; D000953:Antigens, Protozoan / Q000737:chemistry / Q000235:genetics* / Q000276:immunology; D000954:Antigens, Surface / Q000737:chemistry / Q000235:genetics* / Q000276:immunology; D001483:Base Sequence; D000939:Epitopes; D016829:Giardia lamblia / Q000276:immunology*; D008969:Molecular Sequence Data; D009693:Nucleic Acid Hybridization; D015800:Protozoan Proteins; D012091:Repetitive Sequences, Nucleic Acid
D000911:Antibodies, Monoclonal; D000953:Antigens, Protozoan; D000954:Antigens, Surface; D000939:Epitopes; D015800:Protozoan Proteins; C072464:variant surface protein H7, Giardia lamblia