Insights into the biological significance of alternative splicing in Arabidopsis: functional characterization of a dual-targeted E3 ligase and the SCL30a SR protein

Dissertation presented to obtain the Ph.D degree in Molecular Biology

RNA splicing is an essential step in eukaryotic gene expression during which introns are precisely removed from the precursor-mRNA (pre-mRNA) and exons joined together to form the mature mRNA molecule. The presence of numerous exons per gene enables the splicing machinery to process the same premRNA differently by selectively removing different intronic sequences, thus generating multiple transcripts, and eventually more than one protein, from a single gene. Such alternative splicing pathways have emerged as a key mechanism for generating proteome diversity and functional complexity. The prevalence of alternative splicing in many genomes, including those of higher plants, suggests that this mechanism plays crucial roles in biological processes. To adapt to an environment in constant change, plants, as sessile organisms, have evolved high degrees of both developmental plasticity and stress tolerance, which are ultimately regulated at the genome level. The exceptional versatility associated with gene regulation by alternative splicing is likely to play a prominent role in plant responses to environmental cues, but the biological significance of this posttranscriptional regulatory mechanism in plants remains poorly understood.(...)

Financial support from Fundação para a Ciência e a Tecnologia, Ministério da Educação e Ciência, Portugal, through grant SFRH/BD/28519/2006 awarded to Sofia Domingues de Carvalho