Brenner, Bluma G

Coutsinos, Dimitrios

Invernizzi, Cédric F

Moisi, Daniela

Oliveira, Maureen

Wainberg, Mark A

English

PubMed

Brenner Bluma G

Moisi Daniela

Oliveira Maureen

Coutsinos Dimitrios

Invernizzi Cédric F

Wainberg Mark A

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Retrovirology

Biochemical and virological analysis of the preference for the K65R multi-resistance nucleoside mutation in subtype C viruses

Mark A Wainberg

Cédric F Invernizzi

Dimitrios Coutsinos

Maureen Oliveira

Daniela Moisi

Bluma G Brenner

Crossref

BioMed Central
Page 1 of 1
(page number not for citation purposes)
Retrovirology
Open AccessInvited speaker presentation
Biochemical and virological analysis of the preference for the K65R 
multi-resistance nucleoside mutation in subtype C viruses
Mark A Wainberg*, Cédric F Invernizzi, Dimitrios Coutsinos, 
Maureen Oliveira, Daniela Moisi and Bluma G Brenner
Address: McGill University AIDS Centre, Jewish General Hospital, Montréal, Québec, Canada
* Corresponding author    
Objectives
Patients carrying subtype C viruses in Botswana, Malawi,
and South Africa are prone to develop the K65R mutation
in RT after receiving d4T or ddI/d4T in therapy. We have
studied the effect of subtype C polymorphisms at position
64/65 and at TAM sites (70, 210, 219) in RT on pathway
outcome in cell culture, utilizing N(t)RTI drug pressure
alone and in combination.
Methods
We compared mutations of the subtype B NL4-3 (wt)
sequence at sites 64, 65, 70, 210, 219 with silent polymor-
phisms found in the subtype C consensus sequence. Site-
directed mutagenesis of the NL4-3 (wt) plasmid was used
to generate all mutant plasmids. Selections in MT-2 cells
were performed with each of 3TC, FTC, TDF, ABC, ATC,
d4T, and ddI either alone or in combination. Recom-
binant RT enzymes of both subtype B and C origin were
also studied in cell-free reactions.
Results
Selections with 3TC, FTC, TDF, ABC/3TC and TDF/FTC
did not reveal any significant differences between subtype
B NL4-3 viruses in terms of mutations acquired. However,
exposure of NL4-3 containing subtype C coding
sequences at positions 64/65 to ABC, ATC, d4T, ddI, ABC/
FTC, TDF/3TC and d4T/ddI always resulted in the selec-
tion of K65R. This result was not obtained with viruses
that contained subtype C coding sequences at either posi-
tions 64 or 65 but not both. Most importantly, addition
of the silent polymorphisms at TAM sites eased the pres-
sure for the preferential selection of K65R in the newly cre-
ated NL4-3 (C 64/65/70), NL4-3 (C 64/65/70/219) and
NL4-3 (C 64/65/70/210/219) viruses. We have also
shown that pausing in cell-free RT reactions occurs prefer-
entially at the 64/65 site and that this is entierly template-
driven and is not dependent on the origin of the RT
enzyme employed.
Conclusion
Silent polymorphisms at both positions 64 and 65 favor
the development of K65R in subtype C viruses, but this
effect can be attenuated by silent polymorphisms at TAM
sites 70/210/219. These biochemical and tissue culture
findings are of clinical relevance in view of the fact that
d4T-containing regimens are extensively used in develop-
ing country settings and because the K65R mutation is
also responsible for cross-resistance to multiple members
of the N(t)RTI family of drugs. Thus, many second line
regimens that might otherwise be considered after failure
of a d4T-based regimen might no longer be useful in
patients with subtype C viruses.
from Frontiers of Retrovirology: Complex retroviruses, retroelements and their hosts
Montpellier, France. 21-23 September 2009
Published: 24 September 2009
Retrovirology 2009, 6(Suppl 2):I18 doi:10.1186/1742-4690-6-S2-I18
<supplement> <title> <p>Frontiers of Retrovirology: Complex retroviruses, retroelements and their hosts</p> </title> <note>Meeting abstracts - A single PDF containing all abstracts in this Supplement is available <a href="http://www.biomedcentral.com/content/files/pdf/1742-4690-6-S2-full.pdf">here</a>.</note> <url>http://www.biomedcentral.com/content/pdf/1742-4690-6-S2-info.pdf</url> </supplement>
This abstract is available from: http://www.retrovirology.com/content/6/S2/I18
© 2009 Wainberg et al; licensee BioMed Central Ltd. 


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Biochemical and virological analysis of the preference for the K65R multi-resistance nucleoside mutation in subtype C viruses

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