Biosynthesis of the glycosyl phosphatidylinositol anchor of Trypanosoma brucei variant surface glycoprotein

1990 ◽  
Vol 18 (5) ◽  
pp. 722-724 ◽  
Author(s):  
WAYNE J. MASTERSON
Keyword(s):  
Trypanosoma Brucei ◽  
Surface Glycoprotein ◽  
Variant Surface Glycoprotein ◽  
Glycosyl Phosphatidylinositol

scholarly journals Synchronous expression of individual metacyclic variant surface glycoprotein genes in Trypanosoma brucei

2015 ◽  
Vol 200 (1-2) ◽  
pp. 1-4 ◽  
Author(s):  
Kiantra Ramey-Butler ◽  
Elisabetta Ullu ◽  
Nikolay G. Kolev ◽  
Christian Tschudi
Keyword(s):  
Trypanosoma Brucei ◽  
Surface Glycoprotein ◽  
Variant Surface Glycoprotein

Stability and reconstitution of the soluble variant surface glycoprotein (sVSG) from Trypanosoma brucei

Biochemistry ◽  
1990 ◽  
Vol 29 (36) ◽  
pp. 8217-8223 ◽  
Author(s):  
Paul Rehaber ◽  
Norbert Staudacher ◽  
Robert Seckler ◽  
Roland Buelow ◽  
Peter Overath ◽  
...  
Keyword(s):  
Trypanosoma Brucei ◽  
Surface Glycoprotein ◽  
Variant Surface Glycoprotein

Frequent independent duplicative transpositions activate a single VSG gene

1987 ◽  
Vol 7 (1) ◽  
pp. 357-364
Author(s):  
M G Lee ◽  
L H Van der Ploeg
Keyword(s):  
Gene Conversion ◽  
Trypanosoma Brucei ◽  
Surface Antigen ◽  
Strong Evidence ◽  
Base Pair ◽  
Surface Glycoprotein ◽  
Variant Surface Glycoprotein ◽  
Gene Variants ◽  
Repeat Array ◽  
Expression Site

The expression of several surface antigen genes in Trypanosoma brucei is mediated by the duplicative transposition of a basic-copy variant surface glycoprotein (VSG) gene into an expression site. We determined that the appearance of variant 118, in a parasitemia, resulted from at least four independent duplicative transpositions of the same VSG 118 gene. Variants 117 and 118 both appeared at specific periods but resulted from multiple independent activations. Antigenic variants thus occur in an ordered manner. We show that in the duplicative transpositions of VSG genes, the ends of the transposed segments were homologous between the basic copy and the expression site. Sequences other than the previously reported 70-base-pair (bp) repeats could be involved. In one variant, 118 clone 1, the homology was between a sequence previously transposed into the expression site and a sequence located 6 kilobases upstream of the VSG 118 gene. In variant 118b the homology was presumably in 70-bp repeat arrays, while in a third 118 variant yet another sequence was involved. The possibility that the 70-bp repeats are important in the initial steps of the recombinational events was illustrated by a rearrangement involving a 70-bp repeat array. The data provide strong evidence for the notion that gene conversion mediates the duplicative transposition of VSG genes. We discuss a model that explains how the process of duplicative transposition can occur at random and still produce an ordered appearance of variants.

Transient activity assays of the Trypanosoma brucei variant surface glycoprotein gene promoter: control of gene expression at the posttranscriptional level

1991 ◽  
Vol 11 (1) ◽  
pp. 338-343
Author(s):  
D Jefferies ◽  
P Tebabi ◽  
E Pays
Keyword(s):  
Trypanosoma Brucei ◽  
Gene Promoter ◽  
Surface Glycoprotein ◽  
Variant Surface Glycoprotein ◽  
Gene Promoters ◽  
Control Of Gene Expression ◽  
Transient Activity ◽  
Expression Site ◽  
Cat Gene ◽  
Cat Expression

The putative promoter of the variant surface glycoprotein (VSG) gene of Trypanosoma brucei was cloned into a plasmid containing the chloramphenicol acetyltransferase (CAT) gene. After electroporation into trypanosomes, this construct directed the expression of the CAT reporter gene. The essential region for promoter activity was found to reside within 88 bp upstream of the putative transcription start site. Transcription of the CAT construct occurred at approximately the same level in both bloodstream and procyclic forms and was resistant to alpha-amanitin. However, CAT expression appeared to be modulated in the two forms of the parasite. Sequences 3' to the gene seemed to be important in this respect, as CAT activity in bloodstream forms was readily detectable only when the 3' region of a VSG cDNA was placed downstream of the CAT gene. Two separate VSG gene promoter sequences, both cloned from T. brucei AnTat 1.3A, were equally able to direct CAT expression, which suggests that there are a number of potential VSG gene promoters in the genome, although usually only one expression site is fully active at any one time.

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