美国哈佛大学刘如谦（David R. Liu）研究小组开发出可用于RNA定点m6A修饰的Cas13工具。这一研究成果于2020年6月29日在线发表在《自然—生物技术》上。
Title: Programmable m 6 A modification of cellular RNAs with a Cas13-directed methyltransferase
Author: Christopher Wilson, Peter J. Chen, Zhuang Miao, David R. Liu
Abstract: N6-Methyladenosine (m6A) is the most widespread internal messenger RNA modification in humans. Despite recent progress in understanding the biological roles of m6A, the inability to install m6A site specifically in individual transcripts has hampered efforts to elucidate causal relationships between the presence of a specific m6A and phenotypic outcomes. In the present study, we demonstrate that nucleus-localized dCas13 fusions with a truncated METTL3 methyltransferase domain and cytoplasm-localized fusions with a modified METTL3:METTL14 methyltransferase complex can direct site-specific m6A incorporation in distinct cellular compartments, with the former fusion protein having particularly low off-target activity. Independent cellular assays across multiple sites confirm that this targeted RNA methylation (TRM) system mediates efficient m6A installation in endogenous RNA transcripts with high specificity. Finally, we show that TRM can induce m6A-mediated changes to transcript abundance and alternative splicing. These findings establish TRM as a tool for targeted epitranscriptome engineering that can reveal the effect of individual m6A modifications and dissect their functional roles. The most abundant RNA modification in humans, m6A, can be installed at specified RNA sequences in cells, enabling functional studies.