The regulation of biallelic gene expression is important for development in diploid organisms and is associated with several human diseases. Recent studies mainly focused on the DNA level and indicated that allele-specific DNA methylation is one of the factors that influence allele-specific expression.Besides, various RNA modifications have been reported as RNA plays the link role in the process of transcription and translation. However, whether modifications occurring at the RNA level harbor allele-specificity across tissues and species remains unknown.

In a recent study published in Nucleic Acids Research, Prof. ZHANG Yaping's team at Kunming Institute of Zoology of Chinese Academy of Sciences studied allele-specific RNA editing in various tissues of human and mouse.RNA editing is a common modification at RNA level that has important implications on the organism’s genetic diversity.Researchers documented 315 allele-specific RNA editing sites, a large proportion of which overlap between transcriptomes from different human tissues. Meanwhile, they identified 184 allele-specific editing sites in brain tissues of heterozygous mice generated by crosses between divergent mouse strains, a large proportion of which overlap in different samples.The results suggested that the method of identifying allele-specific RNA editing is credible, and indicated that allele-specific RNA editing is ubiquitous.Interestingly, they found that some allele-specific RNA editing sites caused amino acids changes, whereas, a Single Nucleotide Polymorphisms (SNP) adjacent to one of these sites bears synonymous mutational effects.Cellular experiments revealed that the synonymous mutation affects the nonsynonymous editing efficiency, which highlighted the likelihood of the synonymous SNP leading to amino acid changes through allele-specific RNA editing.

Furthermore, SHAPE experiment indicated that allele-specific RNA editing was influenced by differences in local RNA secondary structure generated by SNPs.The study represented an exemplary allele-specific RNA editing research and provided new insight into the connection between synonymous mutations and both diseases and complex traits.This work was supported by grants from Ministry of Agriculture of China and National Natural Science Foundation of China.