Dataset Information

Quantitation of HIV DNA integration: effects of differential integration site distributions on Alu-PCR assays.

ABSTRACT: In many studies of HIV replication, it is useful to quantify the number of HIV proviruses in cells against a background of unintegrated forms of the HIV DNA. A popular method for doing so involves quantitative PCR using one primer complementary to the HIV long terminal repeat (LTR), and a second primer complementary to a cellular Alu repeat, so that PCR product only forms from templates where a provirus is integrated in the human genome near an Alu repeat. However, several recent studies have identified conditions that alter distributions of HIV integration sites relative to genes. Because Alu repeats are enriched in gene rich regions, this raises the question of whether altered integration site distributions might confound provirus abundance measurements using the Alu-PCR method. Here modified versions of the HIV tethering protein LEDGF/p75 were used to retarget HIV integration outside of transcription units, and show that this has a negligible effect on Alu-PCR quantitation of proviral abundance. Thus altered integration targeting, at least to the degree achieved here, is not a major concern when using the Alu-PCR assay.

SUBMITTER: Brady T

PROVIDER: S-EPMC3608829 | biostudies-literature | 2013 Apr

REPOSITORIES: biostudies-literature

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Quantitation of HIV DNA integration: effects of differential integration site distributions on Alu-PCR assays.

Brady Troy T Kelly Brendan J BJ Male Frances F Roth Shoshannah S Bailey Aubrey A Malani Nirav N Gijsbers Rik R O'Doherty Una U Bushman Frederic D FD

Journal of virological methods 20130121 1

In many studies of HIV replication, it is useful to quantify the number of HIV proviruses in cells against a background of unintegrated forms of the HIV DNA. A popular method for doing so involves quantitative PCR using one primer complementary to the HIV long terminal repeat (LTR), and a second primer complementary to a cellular Alu repeat, so that PCR product only forms from templates where a provirus is integrated in the human genome near an Alu repeat. However, several recent studies have id ...[more]

PMID: 23348058

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Project description:BackgroundLigation-mediated PCR protocols have diverse uses including the identification of integration sites of insertional mutagens, integrating vectors and naturally occurring mobile genetic elements. For approaches that employ NGS sequencing, the relative abundance of integrations within a complex mixture is typically determined through the use of read counts or unique fragment lengths from a ligation of sheared DNA; however, these estimates may be skewed by PCR amplification biases and saturation of sequencing coverage.ResultsHere we describe a modification of our previous splinkerette based ligation-mediated PCR using a novel Illumina-compatible adapter design that prevents amplification of non-target DNA and incorporates unique molecular identifiers. This design reduces the number of PCR cycles required and improves relative quantitation of integration abundance for saturating sequencing coverage. By inverting the forked adapter strands from a standard orientation, the integration-genome junction can be sequenced without affecting the sequence diversity required for cluster generation on the flow cell. Replicate libraries of murine leukemia virus-infected spleen samples yielded highly reproducible quantitation of clonal integrations as well as a deep coverage of subclonal integrations. A dilution series of DNAs bearing integrations of MuLV or piggyBac transposon shows linearity of the quantitation over a range of concentrations.ConclusionsMerging ligation and library generation steps can reduce total PCR amplification cycles without sacrificing coverage or fidelity. The protocol is robust enough for use in a 96 well format using an automated liquid handler and we include programs for use of a Beckman Biomek liquid handling workstation. We also include an informatics pipeline that maps reads, builds integration contigs and quantitates integration abundance using both fragment lengths and unique molecular identifiers. Suggestions for optimizing the protocol to other target DNA sequences are included. The reproducible distinction of clonal and subclonal integration sites from each other allows for analysis of populations of cells undergoing selection, such as those found in insertional mutagenesis screens.

Dataset Information

Quantitation of HIV DNA integration: effects of differential integration site distributions on Alu-PCR assays.

Publications

Quantitation of HIV DNA integration: effects of differential integration site distributions on Alu-PCR assays.

Similar Datasets

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