A gene encoding a 69-kilodalton major surface protein of Giardia intestinalis trophozoites

Mol Biochem Parasitol. 1993 Apr;58(2):247-57. doi: 10.1016/0166-6851(93)90046-z.


A gene encoding a 68.5-kDa trophozoite surface protein (TSP11) of the Australian Giardia intestinalis (syn. G. lamblia) isolate, Ad-1, has been cloned from a genomic expression library screened with an antiserum specific for 3 major surface antigens. Sequence analysis of two overlapping genomic fragments identified a single open reading frame that contained no introns and predicted a cysteine-rich, 667-residue polypeptide with features common to other trophozoite surface proteins. These include the presence of 27 copies of the 4-amino acid Cys-X-X-Cys motif, an N-terminal signal sequence and a highly conserved, hydrophobic C-terminal segment. Transcripts from the tsp11 gene were detected as a single band on Northern blots using total RNA extracted from Ad-1 trophozoites. Primer extension analysis indicated that the mRNA has a 5' untranslated region of only 5 nt, similar to the very short (1-6 nt) leader sequences reported for other Giardia mRNAs. A large portion of the promoter distal segment of tsp11 has homology with tsa417, a gene encoding a 72.5-kDa trophozoite surface antigen of the Afghanistan-derived G. intestinalis isolate, WB [13].

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Antigens, Surface / chemistry
  • Antigens, Surface / genetics
  • Base Sequence
  • Chromosome Mapping
  • DNA, Protozoan / genetics
  • Genes, Protozoan*
  • Giardia lamblia / genetics*
  • Giardia lamblia / immunology
  • Molecular Sequence Data
  • Molecular Weight
  • Protozoan Proteins / chemistry
  • Protozoan Proteins / genetics*
  • Protozoan Proteins / immunology
  • RNA, Messenger / genetics
  • RNA, Protozoan / genetics
  • Sequence Homology, Amino Acid


  • Antigens, Surface
  • DNA, Protozoan
  • Protozoan Proteins
  • RNA, Messenger
  • RNA, Protozoan

Associated data

  • GENBANK/M95814