The SERRATE protein is involved in alternative splicing in Arabidopsis thaliana.

Zofia Szweykowska-Kulinska,John W S Brown,Artur Jarmolowski,Mateusz Bajczyk,Malgorzata Kalak,Katarzyna Dorota Raczynska,Craig G Simpson,Jim Mcnicol,Agata Stepien,Daniel Kierzkowski

doi:10.1093/nar/gkaa045

Abstract

How alternative splicing (AS) is regulated in plants has not yet been elucidated. Previously, we have shown that the nuclear cap-binding protein complex (AtCBC) is involved in AS in Arabidopsis thaliana. Here we show that both subunits of AtCBC (AtCBP20 and AtCBP80) interact with SERRATE (AtSE), a protein involved in the microRNA biogenesis pathway. Moreover, using a high-resolution reverse transcriptase-polymerase chain reaction AS system we have found that AtSE influences AS in a similar way to the cap-binding complex (CBC), preferentially affecting selection of 5' splice site of first introns. The AtSE protein acts in cooperation with AtCBC: many changes observed in the mutant lacking the correct SERRATE activity were common to those observed in the cbp mutants. Interestingly, significant changes in AS of some genes were also observed in other mutants of plant microRNA biogenesis pathway, hyl1-2 and dcl1-7, but a majority of them did not correspond to the changes observed in the se-1 mutant. Thus, the role of SERRATE in AS regulation is distinct from that of HYL1 and DCL1, and is similar to the regulation of AS in which CBC is involved.

Highlights

Alternative splicing (AS) is a widespread process that generates more than one spliced mRNA isoform from the same gene
We have shown that the nuclear cap-binding protein complex (AtCBC) is involved in alternative splicing (AS) in Arabidopsis thaliana. We show that both subunits of AtCBC (AtCBP20 and AtCBP80) interact with SERRATE (AtSE), a protein involved in the microRNA biogenesis pathway
We found that changes observed in the se-1 mutant did not correspond with the changes observed in Arabidopsis mutants of other key proteins that interact with Arabidopsis mutants of SERRATE (AtSE), and are involved in plant miRNA biogenesis, hyl1-2 and dcl1-7, suggesting that SERRATE has a function in regulation of AS in plants, which is distinct from its role in miRNA biogenesis

Summary

Introduction

Alternative splicing (AS) is a widespread process that generates more than one spliced mRNA isoform from the same gene. AS can modulate gene expression through the production of mRNA isoforms, which are degraded by NMD [3,6,9,10,11,12,13]. In both plants and animals, $20% of all AS events take place within untranslated regions: 50 UTR (12–15%) or 30 UTR (3–6%), which can affect transport and stability of mRNAs, create new initiation codons or polyadenylation sites, generate upstream open reading frames, trigger NMD or shift the reading frame [13,14,15]

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Conclusion