Abstract/Details

RNA aptamer inhibitors of HIV reverse transcriptase: Molecular evolution and determinants of target specificity


2006 2006

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Abstract (summary)

The nature of intermolecular interactions between proteins and nucleic acids is governed by evolutionary constraints imposed on those biological macromolecules. With the development of in vitro selection techniques for nucleic acid aptamers, we have been provided a powerful tool for use in our quest to better understand the influences of molecular evolution on the determinants of target specificity between nucleic acids and proteins. RNA aptamers selected for binding to the reverse transcriptase (RT) of type I human immunodeficiency virus (HIV-1) inhibit the enzyme's activity by competing for primer-template recognition. When expressed in cultured lymphocytes, aptamers protect the cells from viral replication by inhibiting viral genome replication. Two prominent questions follow from these results: (1) Do aptamers preferentially inhibit viral genome replication at specific points during the multi-step process? and (2) What is the breadth of cross-clade efficacy of RT aptamers? I explored these details of aptamer potency against a panel of recombinant HIV-1, HIV-2, and SIVcpz RTs using a series of assays designed to mimic specific steps of viral genome replication. My findings reveal variability in aptamer potency against discrete steps of reverse transcription, as well as dramatic differences in aptamer potency across viral clades. These results can be understood in part as a function of aptamer structural variability and a single amino acid polymorphism in RT within viral populations. This same principle is evidenced by a project that had nothing to do with HIV-1, but everything to do with the evolution of molecular recognition. Specifically, analysis of the evolutionary pathways between aptamers selected for binding to the nucleotide cofactor FAD and mononucleotide GMP reveals that functional sequence space is very plastic even between less-closely related targets for aptamer binding. Overall, the results from these two projects suggest that despite readily available evolutionary pathways by which HIV could achieve resistance to certain aptamers, broad-spectrum aptamer therapeutics may still be available.

Indexing (details)


Subject
Molecular biology;
Biochemistry
Classification
0307: Molecular biology
0487: Biochemistry
Identifier / keyword
Pure sciences; Biological sciences; HIV reverse transcriptase; RNA aptamer
Title
RNA aptamer inhibitors of HIV reverse transcriptase: Molecular evolution and determinants of target specificity
Author
Held, Daniel M.
Number of pages
177
Publication year
2006
Degree date
2006
School code
0093
Source
DAI-B 67/06, Dissertation Abstracts International
Place of publication
Ann Arbor
Country of publication
United States
ISBN
9780542717772
Advisor
Burke, Donald H.
University/institution
Indiana University
University location
United States -- Indiana
Degree
Ph.D.
Source type
Dissertations & Theses
Language
English
Document type
Dissertation/Thesis
Dissertation/thesis number
3219914
ProQuest document ID
305335174
Copyright
Database copyright ProQuest LLC; ProQuest does not claim copyright in the individual underlying works.
Document URL
http://search.proquest.com/docview/305335174
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