Overexpression and knockdown experiment for circCSNK1G3

Standard RNA analyses using microarrays and low-coverage polyadenylation enriched RNA-Sequencing (RNA-Seq) cannot fully characterize the complexity of the cancer transcriptome. To fully elucidate the transcriptome of prostate tumours, we performed ultra-deep total RNA-Seq on 144 localized prostate tumours with long-term clinical follow up. Analysis of linear RNAs identified a transcriptomic subtype associated with the aggressive intraductal carcinoma subhistology, and a fusion gene profile that differentiates localized from metastatic prostate cancers. Analysis of back-splicing events identified widespread RNA circularization, with the average tumour expressing 7,140 distinct circular RNAs. The degree of aberrant circRNA production is correlated to disease progression in multiple clinical cohorts. Loss of function screens identified 11.3% of the screened circRNAs as essential to prostate cancer proliferation, and for 93.6% of these, their parental linear genes are not required for proliferation. Follow-up studies on circCSNK1G3 revealed its role in regulating cell cycle progression. Ultra-deep transcriptome sequencing thus provides a more comprehensive view of the linear and circular transcriptional and functional landscapes of localized prostate cancer. RNA-seq after the knockdown and overexpression of circCSNK1G3