01956nas a2200205   4500008004100000245007400041210006900115260001500184300001300199490000700212520125700219100002601476700003001502700002501532700002001557700001601577700002101593700003101614856010501645       2011                        eng d00aSUS1 introns are required for efficient mRNA nuclear export in yeast.0 aSUS1 introns are required for efficient mRNA nuclear export in y  c2011 Oct 1  a8599-6110 v393 a<p>Efficient coupling between mRNA synthesis and export is essential for gene expression. Sus1/ENY2, a component of the SAGA and TREX-2 complexes, is involved in both transcription and mRNA export. While most yeast genes lack introns, we previously reported that yeast SUS1 bears two. Here we show that this feature is evolutionarily conserved and critical for Sus1 function. We determine that while SUS1 splicing is inefficient, it responds to cellular conditions, and intronic mutations either promoting or blocking splicing lead to defects in mRNA export and cell growth. Consistent with this, we find that an intron-less SUS1 only partially rescues sus1&Delta; phenotypes. Remarkably, splicing of each SUS1 intron is also affected by the presence of the other and by SUS1 exonic sequences. Moreover, by following SUS1 RNA and protein levels we establish that nonsense-mediated decay (NMD) pathway and the splicing factor Mud2 both play a role in SUS1 expression. Our data (and those of the accompanying work by Hossain et al.) provide evidence of the involvement of splicing, translation, and decay in the regulation of early events in mRNP biogenesis; and imply the additional requirement for a balance in splicing isoforms from a single gene.</p>1 aCuenca-Bono, Bernardo1 aGarcía-Molinero, Varinia1 aPascual-García, Pau1 aDopazo, Hernán1 aLlopis, Ana1 aVilardell, Josep1 aRodríguez-Navarro, Susana  uhttps://www.clinbioinfosspa.es/content/sus1-introns-are-required-efficient-mrna-nuclear-export-yeast