Recruitment of the NineTeen Complex to the activated spliceosome requires AtPRMT5. Arabidopsis thaliana

In this study, we analyzed the pre-mRNA splicing status in wild-type Col, atprmt5 mutants, and two atprmt5 suppressors (m90 and s215). RNA-seq analyses revealed that m90 and s215 can partially rescue the pre-mRNA splicing defects in atprmt5 mutants. Further study showed that m90 and s215 were identified in the highly conserved pre-mRNA splicing factor 8 (AtPrp8) and demonstrated that Prp19C/NTC complex failed to be assembled into U5 snRNP to form activated spliceosome in atprmt5 mutants, while restored in the suppressor. Our findings uncover a key molecular mechanism for AtPRMT5 in the regulation of pre-mRNA splicing. Overall design: Investigate the pre-mRNA splicing in the suppressors of atprmt5 mutants