qDRIP

qDRIP quantifies RNA–DNA hybrid (R-loop) formation genome-wide by combining quantitative differential DNA–RNA immunoprecipitation with synthetic RNA–DNA-hybrid internal standards and high-resolution, strand-specific next-generation sequencing to enable accurate differential comparisons and estimates of hybrid abundance and half-lives.

Key Features:

• Bias Mitigation: Uses synthetic RNA–DNA-hybrid internal standards to mitigate biases associated with read-count normalization in sequencing-based R-loop profiling.
• Synthetic Internal Standards: Integrates synthetic RNA–DNA-hybrid spike-ins as internal standards for quantitative normalization.
• Strand-specific Next-generation Sequencing: Employs high-resolution, strand-specific sequencing techniques for directional mapping of RNA–DNA hybrids.
• Differential Peak Calling: Performs differential peak calling between experimental conditions to identify changes in R-loop distribution and abundance.
• Quantitative Estimation: Provides quantitative comparisons including estimates of absolute numbers of RNA–DNA hybrids per cell and genome-wide hybrid half-lives.
• Identification of RNase H-resistant Hybrids: Detects subsets of RNA–DNA hybrids with high GC skew that show partial resistance to RNase H.

Scientific Applications:

• Genome-wide R-loop Mapping: Mapping the genomic distribution of R-loops with strand specificity and quantitative normalization.
• Comparative Analysis of R-loop Dynamics: Comparing R-loop abundance and distribution across treatments or perturbations of transcription and resolution mechanisms.
• Quantification of Hybrid Abundance and Kinetics: Estimating absolute counts of RNA–DNA hybrids per cell and their half-lives genome-wide.
• Characterization of RNase H-resistant Hybrids: Identifying and characterizing hybrid subsets with high GC skew and partial RNase H resistance.
• Study of Transcriptional Regulation and Genome Stability: Investigating consequences of altered R-loop dynamics for transcriptional regulation and DNA damage or genome stability.

Methodology:

Implements quantitative differential DNA–RNA immunoprecipitation (qDRIP) by integrating synthetic RNA–DNA-hybrid internal standards with high-resolution, strand-specific next-generation sequencing and differential peak calling to mitigate read-count normalization biases.