Subcellular localization and putative functions of alternative splicing isoforms in Arabidopsis thaliana.

RODRÍGUEZ, FLORENCIA S.; SERVI, LUCAS; CARTAGENA, CARLA M.; TOGNACCA, ROCÍO S.; PETRILLO, EZEQUIEL

Mendoza

Congreso; LVIII Reunión Anual de SAIB; 2022

SAIB

Alternative splicing (AS) produces multiple transcripts (variants or isoforms) from a single genethrough the variable and regulated usage of different splicing sites, significantly modulating thetranscriptome, and to some extent the proteome, during development and in response toenvironmental cues. In addition to generating different isoforms that can be translated into differentproteins, this process can also give rise to variants without coding capacity. Some of these aredegraded, allowing delicate regulation of the amount of protein generated. However, others aresubstantially stable. Interestingly, non-coding transcripts can control chromatin status, modulate theabundance of other RNAs (miRNAs, lncRNAs, mRNAs, etc.), and even translation. By usingpublicly available RNAseq datasets linked to RNA translation, non-sense mediated mRNAdecay and subcellular localization, we found that certain non-coding isoforms of a set ofgenes of interest are not degraded, despite the presence of NMD associated sequences, asthey accumulate in the nucleus. To validate these data, the subcellular localization of thedifferent isoforms of RS31 and other genes of interest (SR30, U2AF65) was evaluated.Consistently, certain isoforms that retain intronic sequences are kept in the nucleus. Wehypothesize that these non-coding transcripts could be fulfilling a nuclear regulatoryfunction, acting as lncRNA generated by alternative splicing of coding genes. Therefore,transgenic plants that overexpress each particular isoform were generated, and theirphenotype was compared with that of wildtype plants. Next, we will determine if the non-coding isoforms regulate the activity of the protein coded by the same gene.