LUMI-PCR

"LUMI-PCR" is a modification of the traditional splinkerette-based ligation-mediated PCR protocol, specifically designed to improve the identification and quantitative analysis of integration sites of insertional mutagens, integrating vectors, and naturally occurring mobile genetic elements in next-generation sequencing (NGS) applications. Addressing common issues such as PCR amplification biases and saturation of sequencing coverage, LUMI-PCR incorporates a novel Illumina-compatible adapter design that enhances the accuracy and efficiency of sequencing integration-genome junctions.

Key Features and Improvements:

- Novel Adapter Design: The innovative adapter design prevents the amplification of non-target DNA and includes unique molecular identifiers (UMIs), crucial for reducing PCR cycle requirements and improving the relative quantitation of integration abundance.

- Improved Quantitation: By optimizing the adapter orientation and incorporating UMIs, LUMI-PCR offers more accurate quantitation of integration sites, which is especially valuable for assessing the relative abundance of integrations within complex mixtures.

- Reduced PCR Amplification Cycles: Integrating ligation and library generation steps significantly reduces the total number of PCR amplification cycles needed, enhancing coverage and fidelity without increasing sequencing errors or biases.

- Reproducible Results: Validation experiments, including replicate libraries from murine leukemia virus-infected spleen samples, demonstrated highly reproducible quantitation of both clonal and subclonal integrations, showcasing the protocol's reliability.

- Linear Quantitation Over Concentration Ranges: A dilution series with DNAs bearing integrations of MuLV or piggyBac transposon illustrated the linearity of quantitation across a range of concentrations, emphasizing the protocol's accuracy in quantifying integration abundance.

- Automation and High-throughput Compatibility: LUMI-PCR is designed for high-throughput execution, including compatibility with 96 well formats and automation via liquid handling workstations, making it suitable for large-scale studies.

- Informatics Pipeline: Accompanying the protocol is an informatics pipeline for mapping reads, building integration contigs, and quantitating integration abundance using fragment lengths and UMIs, streamlining the analysis process.

Applications and Implications:

LUMI-PCR is particularly useful for researchers studying the genomic integration of viruses, transposons, or other mobile genetic elements and their implications in gene function, evolution, and disease. The protocol's robustness and reproducibility make it an invaluable tool for insertional mutagenesis screens and for analyzing cell populations undergoing selection or therapy-induced evolution.