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Abstract Background Studies on biological functions of N6‐methyladenosine (m6A) modification in mRNA have sprung up in recent years. Previous studies have reported m6A can determine mRNA fate and play a pivotal role in tumour development and progression. The zinc finger protein 677 (ZNF677) belongs to the zinc finger protein family and possesses transcription factor activity by binding sequence‐specific DNA. Methods The expression of ZNF677 and its clinicopathological impact were evaluated in renal cell carcinoma (RCC) patients. The m6A level of ZNF677 was determined by m6A methylated RNA immunoprecipitation‐sequencing (MeRIP‐seq) and MeRIP‐qPCR in RCC tissues and adjacent normal tissues. RNA immunoprecipitation‐qPCR (RIP‐qPCR) and luciferase assays were performed to identify the targeted effect of IGF2BP2 and YTHDF1 on ZNF677. RCC cells and subcutaneous models uncovered the role of ZNF677 methylated by CRISPR/dCas13b‐METTL3 in tumour growth. ZNF677‐binding sites in the CDKN3 promoter were investigated by chromatin immunoprecipitation (ChIP) and luciferase assays. Results ZNF677 is frequently downregulated in RCC tissues and its low expression is associated with unfavourable prognosis and decreased m6A modification level. Further, we find the m6A‐modified coding sequence (CDS) of ZNF677 positively regulates its translation and mRNA stability via binding with YTHDF1 and IGF2BP2, respectively. Targeted specific methylation of ZNF677 m6A by CRISPR/dCas13b‐METLL3 system can significantly increase the m6A and expression level of ZNF677, and dramatically inhibit cell proliferation and induce cell apoptosis of RCC cells. In addition, ZNF677 exerted its tumour suppressor functions in RCC cells through transcriptional repression of CDKN3 via binding to its promoter. In vitro and clinical data confirm the negative roles of ZNF677/CDKN3 in tumour growth and progression of RCC. Conclusion ZNF677 functions as a tumour suppressor and is frequently silenced via m6A modification in RCC, which may highlight m6A methylation‐based approach for RCC diagnosis and therapy.

Abstract As a novel and robust gene‐editing tool, the Clustered Regularly Interspaced Short Palindromic Repeats CRISPR‐associated protein 9 (CRISPR‐Cas9) system has revolutionized gene therapy. Plasmid vector delivery is the most commonly used method for integrating the CRISPR‐Cas9 system into cells. However, such foreign cytosolic DNAs trigger an innate immune response (IIR) within cells, which can hinder gene editing by inhibiting transgene expression. Although some small molecules have been shown to avoid the action of IIR on plasmids, they only work on a single target and may also affect cell viability. A genetic approach that works at a comprehensive level for manipulating IIR is still lacking. Here, we designed and constructed several artificial nucleic acid molecules (ANAMs), which are combinations of aptamers binding to two key players of IIR (β‐catenin and NF‐κB). ANAMs strongly inhibited the IIR in cells, thus improving transgene expression. We also used ANAMs to improve the gene‐editing efficiency of the CRISPR‐Cas9 system and its derivatives, thus enhancing the apoptosis of cancer cells induced by CRISPR‐Cas9. ANAMs can be valuable tools for improving transgene expression and gene editing in mammalian cells.