CASPR – an analysis pipeline for single and paired guide RNA CRISPR screens, reveals optimal target selection for long noncoding RNAs

CRISPR-Cas9 loss-of-function pooled screening promises to identify which long noncoding RNAs (lncRNAs), amongst the many thousands to have been annotated so far, are capable of mediating cellular functions. The two principal loss-of-function perturbations, CRISPR-inhibition and CRISPR-deletion, employ one and two guide RNAs, respectively. However, no software solution has the versatility to identify hits across both modalities, and the optimal design parameters for such screens remain poorly understood.

Researchers at Bern University Hospital have developed CASPR (CRISPR Analysis for Single and Paired RNA-guides), a user-friendly, end-to-end screen analysis tool. CASPR is compatible with both CRISPRi and CRISPR-del screens, and balances sensitivity and specificity by generating consensus predictions from multiple algorithms. Benchmarking on ground-truth sets of cancer-associated lncRNAs demonstrates CASPR’s improved sensitivity with respect to existing methods. Applying CASPR to published screens, the researchers identify two parameters that predict lncRNA hits: expression, and annotation quality of the transcription start site. Thus CASPR is a versatile and complete solution for lncRNA CRISPR screen analysis, and reveals principles for including lncRNAs in screening libraries.

Comprehensive CASPR results from this study, across cell types, perturbations and algorithms

lncRNA

A. Number of lncRNA hits at an FDR < 0.01 identified with CASPR (dark blue), and CB2 (lighter blues), in the CRISPRi screen analyses of MCF7 and U87. B, C. Overlap between CASPR and CB2 hits in MCF7 and U87. D. Precision and sensitivity of CASPR and CB2 at an FDR < 0.01 in MCF7 and U87. E, F. ROC Curves and AUC comparing the performance of CASPR and CB2 in MCF7 and U87. G, H. ROC Curves and AUC comparing the performance of CASPR and CB2 in a CRISPR-del and CRISPRi screen based on protein coding genes in RT112.

Availability: https://judithbergada.github.io/CASPR/

Bergadà-Pijuan J, Pulido-Quetglas C, Vancura A, Johnson R. (2019) CASPR, an analysis pipeline for single and paired guide RNA CRISPR screens, reveals optimal target selection for long noncoding RNAs. Bioinformatics [Epub ahead of print]. [abstract]

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