biostudies-literatureMangilet AFDeutsche ForschungsgemeinschaftDeutsche Forschungsgemeinschaft (German Research Foundation)1514-1531https://www.ebi.ac.uk/biostudies/studies/S-EPMC11489095biostudies-literatureUnknown10(10)The removal of introns by the spliceosome is a key gene regulatory mechanism in eukaryotes, with the U1 snRNP subunit playing a crucial role in the early stages of splicing. Studies in metazoans show that the U1 snRNP also conducts splicing-independent functions, but the lack of genetic tools and knowledge about U1 snRNP-associated proteins have limited the study of such splicing-independent functions in plants. Here we describe an RNA-centric approach that identified more than 200 proteins associated with the Arabidopsis U1 snRNP and revealed a tight link to mRNA cleavage and polyadenylation factors. Interestingly, we found that the U1 snRNP protects mRNAs against premature cleavage and polyadenylation within introns-a mechanism known as telescripting in metazoans-while also influencing aNature plantsThe Arabidopsis U1 snRNP regulates mRNA 3'-end processing.PMC11489095LA2633-4/2400681449/GRK2498 TP13Nagel LSchmidtke CWeber JRot GHeilmann PSchmutzer TMjema EYRenneberg MLaubinger SHerold ADroste-Borel IAdler MMangilet AFSchuler SStreicher SMacek BfalseThe Arabidopsis U1 snRNP regulates mRNA 3'-end processing.The removal of introns by the spliceosome is a key gene regulatory mechanism in eukaryotes, with the U1 snRNP subunit playing a crucial role in the early stages of splicing. Studies in metazoans show that the U1 snRNP also conducts splicing-independent functions, but the lack of genetic tools and knowledge about U1 snRNP-associated proteins have limited the study of such splicing-independent functions in plants. Here we describe an RNA-centric approach that identified more than 200 proteins associated with the Arabidopsis U1 snRNP and revealed a tight link to mRNA cleavage and polyadenylation factors. Interestingly, we found that the U1 snRNP protects mRNAs against premature cleavage and polyadenylation within introns-a mechanism known as telescripting in metazoans-while also influencing a2024-01-01T00:00:00Z2024 Oct2025-04-04T01:11:31.259Z2025-04-04T01:11:31.259ZS-EPMC114890953931356210.1038/s41477-024-01796-8