CRISPR-Cas9 (Clustered regularly interspaced short palindromic repeats-associated nuclease 9) systems, the versatile and convenient tools for genome editing and epigenome modulation, have been applied in various genomic screen studies. Compared with conventional RNAi screens, CRISPR screens incur less off-target effects and can be used in multiple formats and can target both coding and noncoding regions throughout the genome. CRISPR screens have been applied to various functional genomic studies such as identifying genes essential for cell survival, genes involved in resistance to drugs or toxins and genes promoting cancer cell metastasis. Future improvements in sgRNA/Cas9 design, synthesis, selection and delivery will help to improve the specificity and efficiency of CRISPR screen. Given the rapid advance in this area, we can optimistically envisage that in the near future CRISPR screen might transform functional genomic researches. (By Drs. Ji Li-Juan and Lu Xiao-Jie, http://jmg.bmj.com/content/early/2015/12/16/jmedgenet-2015-103409 )

Dr. Ji Li-Juan