scholarly journals Variation in repeat copy number of the Epithelial adhesin 1 tandem repeat region leads to variable protein display through multiple mechanisms

2019 ◽  
Author(s):  
Colin J. Raposo ◽  
Kyle A. McElroy ◽  
Stephen M. Fuchs
Keyword(s):  
Cell Surface ◽  
Tandem Repeat ◽  
Copy Number ◽  
Surface Display ◽  
Host Tissue ◽  
Repeat Region ◽  
Repeat Copy Number ◽  
Tandem Repeat Region ◽  
Linker Domain ◽  
Repeat Copy

AbstractThe pathogenic yeast Candida glabrata is reliant on a suite of cell surface adhesins that play a variety of roles necessary for transmission, establishment, and proliferation during infection. One particular adhesin, Epithelial Adhesin 1 [Epa1p], is responsible for binding to host tissue, a process which is essential for fungal propagation. Epa1p structure consists of three domains: an N-terminal intercellular binding domain responsible for epithelial cell binding, a C-terminal GPI anchor for cell wall linkage, and a serine / threonine-rich linker domain connecting these terminal domains. The linker domain contains a 40-amino acid tandem repeat region, which we have found to be variable in repeat copy number between isolates from clinical sources. We hypothesized that natural variation in Epa1p repeat copy may modulate protein function. To test this, we recombinantly expressed Epa1p with various repeat copy numbers in S. cerevisiae to determine how differences in repeat copy number affect Epa1p expression, surface display, and binding to human epithelial cells. Our data suggest that repeat copy number variation has pleiotropic effects, influencing gene expression, protein surface display, shedding from the cell surface, and host tissue adhesion of the Epa1p adhesin. Understanding these links between repeat copy number variants and mechanisms of infection provide new understanding of the variety of roles of repetitive proteins contribute to pathogenicity of C. glabrata.

scholarly journals The Epithelial adhesin 1 tandem repeat region mediates protein display through multiple mechanisms

2020 ◽  
Vol 20 (3) ◽  
Author(s):  
Colin J Raposo ◽  
Kyle A McElroy ◽  
Stephen M Fuchs
Keyword(s):  
Cell Surface ◽  
Protein Function ◽  
Copy Number ◽  
Surface Display ◽  
Repeat Region ◽  
Repeat Copy Number ◽  
Number Variation ◽  
Tandem Repeat Region ◽  
Linker Domain ◽  
Repeat Copy

ABSTRACT The pathogenic yeast Candida glabrata is reliant on a suite of cell surface adhesins that play a variety of roles necessary for transmission, establishment and proliferation during infection. One particular adhesin, Epithelial Adhesin 1 [Epa1p], is responsible for binding to host tissue, a process which is essential for fungal propagation. Epa1p structure consists of three domains: an N-terminal intercellular binding domain responsible for epithelial cell binding, a C-terminal GPI anchor for cell wall linkage and a serine/threonine-rich linker domain connecting these terminal domains. The linker domain contains a 40-amino acid tandem repeat region, which we have found to be variable in repeat copy number between isolates from clinical sources. We hypothesized that natural variation in Epa1p repeat copy may modulate protein function. To test this, we recombinantly expressed Epa1p with various repeat copy numbers in S. cerevisiae to determine how differences in repeat copy number affect Epa1p expression, surface display and binding to human epithelial cells. Our data suggest that repeat copy number variation has pleiotropic effects, influencing gene expression, protein surface display and shedding from the cell surface of the Epa1p adhesin. This study serves to demonstrate repeat copy number variation can modulate protein function through a number of mechanisms in order to contribute to pathogenicity of C. glabrata.

Variation in primary sequence and tandem repeat copy number among i-antigens of Ichthyophthirius multifiliis☆

2002 ◽  
Vol 120 (1) ◽  
pp. 93-106 ◽  
Author(s):  
Yuankai Lin ◽  
Tian Long Lin ◽  
Chia-Cheng Wang ◽  
Xuting Wang ◽  
Knut Stieger ◽  
...  
Keyword(s):  
Tandem Repeat ◽  
Copy Number ◽  
Ichthyophthirius Multifiliis ◽  
Primary Sequence ◽  
Repeat Copy Number ◽  
Repeat Copy

scholarly journals Effect of Repeat Copy Number on Variable-Number Tandem Repeat Mutations in Escherichia coli O157:H7

2006 ◽  
Vol 188 (12) ◽  
pp. 4253-4263 ◽  
Author(s):  
Amy J. Vogler ◽  
Christine Keys ◽  
Yoshimi Nemoto ◽  
Rebecca E. Colman ◽  
Zack Jay ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Mismatch Repair ◽  
Mutation Rate ◽  
Tandem Repeat ◽  
Copy Number ◽  
Variable Number Tandem Repeat ◽  
Variable Number ◽  
Mutation Rates ◽  
Repeat Copy Number ◽  
Repeat Copy

ABSTRACT Variable-number tandem repeat (VNTR) loci have shown a remarkable ability to discriminate among isolates of the recently emerged clonal pathogen Escherichia coli O157:H7, making them a very useful molecular epidemiological tool. However, little is known about the rates at which these sequences mutate, the factors that affect mutation rates, or the mechanisms by which mutations occur at these loci. Here, we measure mutation rates for 28 VNTR loci and investigate the effects of repeat copy number and mismatch repair on mutation rate using in vitro-generated populations for 10 E. coli O157:H7 strains. We find single-locus rates as high as 7.0 × 10−4 mutations/generation and a combined 28-locus rate of 6.4 × 10−4 mutations/generation. We observed single- and multirepeat mutations that were consistent with a slipped-strand mispairing mutation model, as well as a smaller number of large repeat copy number mutations that were consistent with recombination-mediated events. Repeat copy number within an array was strongly correlated with mutation rate both at the most mutable locus, O157-10 (r 2 = 0.565, P = 0.0196), and across all mutating loci. The combined locus model was significant whether locus O157-10 was included (r 2 = 0.833, P < 0.0001) or excluded (r 2 = 0.452, P < 0.0001) from the analysis. Deficient mismatch repair did not affect mutation rate at any of the 28 VNTRs with repeat unit sizes of >5 bp, although a poly(G) homomeric tract was destabilized in the mutS strain. Finally, we describe a general model for VNTR mutations that encompasses insertions and deletions, single- and multiple-repeat mutations, and their relative frequencies based upon our empirical mutation rate data.

scholarly journals OC125, M11 and OV197 Epitopes Are Not Uniformly Distributed in the Tandem-Repeat Region of CA125 and Require the Entire SEA Domain

2013 ◽  
Vol 34 (4) ◽  
pp. 257-267 ◽  
Author(s):  
Alessandro Bressan ◽  
Francesca Bozzo ◽  
Carlo Alberto Maggi ◽  
Monica Binaschi
Keyword(s):  
Ovarian Cancer ◽  
Monoclonal Antibodies ◽  
Western Blot ◽  
Tandem Repeat ◽  
Blot Analysis ◽  
Western Blot Analysis ◽  
Human Cancer ◽  
Ovarian Cancer Cells ◽  
Repeat Region ◽  
Tandem Repeat Region

The human cancer antigen 125 (CA125) is over-expressed in epithelial ovarian cancer cells and it plays a role in the pathogenesis of ovarian cancer. This protein presents a repeat region containing up to sixty tandem repeat units. The anti-CA125 monoclonal antibodies have been previously classified into three groups: two major families, the OC125-like antibodies and M11-like antibodies, and a third group, the OV197-like antibodies. A model in which a single repeat unit contains all the epitopes for these antibodies has been also proposed, even if their exact position is still undetermined. In the present work, the affinities of the monoclonal antibodies, representative of the three families, have been investigated for different CA125-recombinant repeats through Western blot analysis. Different patterns of antibody recognition for the recombinant repeats show that CA125 epitopes are not uniformly distributed in the tandem repeat region of the protein. The minimal region for the recognition of these antibodies has been also individuated in the SEA domain through the subcloning of deleted sequences of the highly recognized repeat-25 (R-25), their expression as recombinant fragments inE. coliand Western blot analysis. Obtained data have been further confirmed by ELISA using the entire R-25 as coating antigen.

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