This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Reprints and Permissions Copyright Information Books from ASM Press MicrobeWorld Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Adam, R D Articles by Nash, T E Search for Related Content PubMed PubMed Citation Articles by Adam, R D Articles by Nash, T E

 Previous Article  |  Next Article 

Mol Cell Biol. 1992 March; 12(3): 1194-1201

The cysteine-rich protein gene family of Giardia lamblia: loss of the CRP170 gene in an antigenic variant.

Department of Internal Medicine, University of Arizona, Tucson 85724.

ABSTRACT

Giardia lamblia trophozoites demonstrate variable expression of a repertoire of cysteine-rich surface antigens in vitro and in vivo. The size of the repertoire has been estimated at 20 to 184, and specific variants can be detected after approximately 12 generations of in vitro growth for the WB isolate. In earlier studies, we cloned a portion of the gene for a 170-kDa surface antigen (CRP170) and demonstrated by DNA sequencing that it was cysteine rich (12%) and contained 2.6 copies of a tandemly repeated 195-bp pair sequence. The clone hybridized to multiple bands on a Southern blot of G. lamblia DNA in a pattern that was variable among the cloned lines but did not correlate with expression of CRP170. We have now cloned a nearly full length cDNA as well as genomic clones for CRP170 from the WBA6 cloned isolate. In addition, we have isolated a cDNA clone from the WB1269 line (expressing CRP72), an antigenic variant which was derived from WBA6. Sequence analysis of the CRP170 and CRP72 genes revealed marked C-terminal amino acid homology, suggesting a conserved functional role such as membrane anchoring. The CRP170 repeat oligonucleotide hybridized to a stairstep of bands approximately 6 kb in size on HindIII-digested WBA6 DNA representing the expressed copy(ies) of CRP170. In contrast, there was no hybridization to a fragment of similar size in WB1269, suggesting that WB1269 trophozoites have lost the expressed copy of the CRP170 gene.

This article has been cited by other articles:

• Seshadri, V., McArthur, A. G., Sogin, M. L., Adam, R. D. (2003). Giardia lamblia RNA Polymerase II: AMANITIN-RESISTANT TRANSCRIPTION. J. Biol. Chem. 278: 27804-27810 [Abstract] [Full Text]  
• Adam, R. D. (2001). Biology of Giardia lamblia. Clin. Microbiol. Rev. 14: 447-475 [Abstract] [Full Text]  
• Faubert, G. (2000). Immune Response to Giardia duodenalis. Clin. Microbiol. Rev. 13: 35-54 [Abstract] [Full Text]