Overexpression of complementary DNA (cDNA) represents the most commonly used gain-of-function approach for interrogating gene functions and for manipulating biological traits. However, this approach is challenging and inefficient for multigene expression due to increased labor for cloning, limited vector capacity, requirement of multiple promoters and terminators, and variable transgene expression levels. Synthetic transcriptional activators provide a promising alternative strategy for gene activation by tethering an autonomous transcription activation domain (TAD) to an intended gene promoter at endogenous genomic locus through a programmable DNA-binding module. Among the known custom DNA-binding modules, the nuclease-dead Streptococcus pyogenes Cas9 (dCas9) protein, which recognizes a specific DNA target through base pairing between a synthetic guide RNA (sgRNA) and DNA, outperforms zinc finger proteins (ZFPs) and transcription activator-like effectors (TALEs), both of which target through protein-DNA interactions1. Recently, three potent dCas9-based transcriptional activation systems, namely VPR, SAM, and Suntag, have been developed for animal cells2–6. However, an efficient dCas9-based transcriptional activation platform is still lacking for plant cells7–9. Here, we developed a new potent dCas9-TAD named dCas9-TV through plant cell-based screens, which confers far stronger transcriptional activation of a single or multiple target genes than the routinely used dCas9-VP64 activator in both plant and mammalian cells.

Papillary thyroid carcinoma (PTC) is the most common type of thyroid cancer. However, we know little of mutational spectrum in the Chinese population. Thus, here we report the identification of somatic mutations for Chinese PTC using 402 tumor-normal pairs (Discovery: 91 pairs via exome sequencing; validation: 311 pairs via Sanger sequencing). We observed three distinct mutational signatures, evidently different from the two mutational signatures among Caucasian PTCs. Ten significantly mutated genes were identified, most previously uncharacterized. Notably, we found that long non-coding RNA (lncRNA) GAS8-AS1 is the secondary most frequently altered gene and acts as a novel tumor suppressor in PTC. As a mutation hotspot, the c.713A>G/714T>C dinucleotide substitution was found among 89.1% patients with GAS8-AS1 mutations and associated with advanced PTC disease (P = 0.009). Interestingly, the wild-type lncRNA GAS8-AS1 (A713T714) showed consistently higher capability to inhibit cancer cell growth compared to the mutated lncRNA (G713C714). Further studies also elucidated the oncogene nature of the G protein-coupled receptor LPAR4 and its c.872T>G (p.Ile291Ser) mutation in PTC malignant transformation. The BRAF c.1799T>A (p.Val600Glu) substitution was present in 59.0% Chinese PTCs, more frequently observed in patients with lymph node metastasis (P = 1.6 × 10(-4)). Together our study defines a exome mutational spectrum of PTC in the Chinese population and highlights lncRNA GAS8-AS1 and LPAR4 as potential diagnostics and therapeutic targets.

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A functional rs4245739 A>C single nucleotide polymorphism (SNP) locating in the MDM43’-untranslated (3’-UTR) region creates a miR-191-5p or miR-887-3p targeting sites. This change results in decreased expression of oncogene MDM4. Therefore, we examined the association between this SNP and small cell lung cancer (SCLC) risk as well as its regulatory function in SCLC cells. Genotypes were determined in two independent case-control sets consisted of 520SCLC cases and 1040 controls from two regions of China. Odds ratios (ORs) and 95% confidence intervals (CIs) were estimated by logistic regression. The impact of the rs4245739 SNP on miR-191-5p/miR-887-3p mediated MDM4 expression regulation was investigated using luciferase reporter gene assays. We found that the MDM4 rs4245739AC and CC genotypes were significantly associated with decreased SCLC susceptibility compared with the AA genotype in both case-control sets (Shandong set: OR = 0.53, 95% CI = 0.32–0.89, P = 0.014; Jiangsu set: OR = 0.47, 95% CI = 0.26–0.879, P = 0.017). Stratified analyses indicated that there was a significantly multiplicative interaction between rs4245739 and smoking (P interactioin = 0.048). After co-tranfection of miRNAs and different allelic-MDM4 reporter constructs into SCLC cells, we found that the both miR-191-5p and miR-887-3p can lead to significantly decreased MDM4 expression activities in the construct with C-allelic 3’-UTR but not A-allelic 3’-UTR, suggesting a consistent genotype-phenotype correlation. Our data illuminate that the MDM4rs4245739SNP contributes to SCLC risk and support the notion that gene 3’-UTR genetic variants, impacting miRNA-binding, might modify SCLC susceptibility.

a b s t r a c t 5S rRNA plays an important part in ribosome biology and is over-expression in multiple cancers. In this study, we found that 5S rRNA is a direct target of miR-150 and miR-383 in esophageal squamous cell carcinoma (ESCC). Overexpression of miR-150 and miR-383 inhibited ESCC cell proliferation in vitro and in vivo. Moreover, 5S rRNA silencing by miR-150 and miR-383 might intensify rpL11-c-Myc interaction, which attenuated role of c-Myc as an oncogenic transcriptional factor and dysregulation of multiple c-Myc target genes. Taken together, our results highlight the involvement of miRNAs in ribosomal regulation during tumorigenesis.