Orthrus

Orthrus scores combinatorial CRISPR screening data to quantify effects of dual-guide RNA constructs and assess screen quality in multiplexed CRISPR systems such as CHyMErA (Cas9 and Cas12a Hybrid Multiplex Editing of Regulatory Elements).

Key Features:

• Combinatorial scoring: Handles combinatorial CRISPR screens with multiple gRNAs per construct and accounts for variables such as the number of gRNAs per construct and their positional arrangement that can influence gRNA expression, processing, or capture.
• Screen quality assessment: Implements routines for assessing screen quality to evaluate the reliability and accuracy of experimental data.
• Dual guide RNA scoring modes: Offers two scoring modes for dual-guide RNA (dgRNA) designs: same-gene targeting and different-gene targeting.
• Multiplexed platform compatibility: Tailored for multiplexed CRISPR systems, explicitly including CHyMErA and dgRNA-containing constructs.
• Implementation: Provided as an R package for computational analysis of combinatorial CRISPR screens.

Scientific Applications:

• Functional genomics: Enables elucidation of gene functions and redundancy by scoring combinatorial perturbations.
• Pathway analysis: Facilitates analysis of genetic networks and interactions using dual-gene perturbation data.
• Synthetic lethality screening: Supports identification of synthetic lethal interactions for cancer research using dgRNA-based screens.

Methodology:

Processes raw combinatorial CRISPR screening data and applies algorithms to score dual gRNA effects, including data normalization, quality control checks, and statistical analysis tailored to multiplexed design parameters such as number and positional arrangement of gRNAs.