GSE117416
A comprehensive map of intron branchpoints and lariat RNAs in plants
Lariat is formed by excised intron, in which the 5' splice site joints with the branchpoint (BP) during splicing. Although lariat RNAs are usually degraded by DBR1 (RNA debranching enzyme 1), recent findings in animals showed that many lariat RNAs were widely detected under physiological conditions. In contrast, the features of BPs and to what extent lariat RNAs accumulate naturally are largely unexplored in plants. Here, we analyzed 948 RNA sequencing datasets to document plant BPs and lariat RNAs on a genome-wide scale. In total, we identified 13872, 5199, 29582, and 13478 BPs in Arabidopsis, tomato, rice, and maize, respectively. Features of plant BPs are highly similar to those in yeast and human, in that BPs are adenine-preferred and flanked by uracil-enriched sequences. Intriguingly, ~20% of introns harbor multiple BPs, and BP usage is tissue-specific. Furthermore, 10580 lariat RNAs accumulate in wild type Arabidopsis plants, and most of these lariat RNAs originate from longer or retroelement-depleted introns, and the expression of these lariat RNAs significantly correlated with the incidence of back-splicing of parent exons. Collectively, our results provide the first comprehensive map of intron BPs and lariat RNAs in plants, and uncover a novel link between lariat turnover and splicing. Overall design: 8 samples for two geneotypes (Col-0 and dbr1-2) are used for analysis, which includes 4 samples of Rnase R-minus and 4 samples for Rnase R-plus samples. Both Col-0 and dbr1-2 has two replicates for Rnase R-minus and Rnase R-plus, respectively