Thursday 10 January 2019, 1.00PM
Speaker(s): Professor Daniela Delneri, University of Manchester
The Saccharomyces cerevisiae genome has undergone extensive intron loss during its evolutionary history, and the few remaining may be retained because of their impact on function in specific environmental conditions. We explored the possibility that new functional ncRNAs are embedded within intronic sequences and are responsible to intron retention in yeast. We employed de novo RNA structure prediction tools to screen intronic sequences in 37 fungi, and we identified and validated 19 novel intronic RNAs via RT-PCR. We deleted the novel intronic RNA structure within the GLC7 intron and showed that this region, rather than the intron itself, is responsible for the cell's ability to respond to salt stress. RNA-seq analysis confirmed that introns in ribosomal protein genes are more highly expressed when they contain predicted RNA structures. Overall, these data support the notion that some introns may have been maintained in the genome because they harbor important RNA structures (Ref 1).
We have also constructed a barcoded ncRNA deletion collection in S. cerevisiae (ca. 500 mutants; Ref 2, Ref 3), and are currently creating phenotypic and genetic interaction maps of ncRNAs in S. cerevisiae by exploiting (i) fitness analysis of double KO mutants generated using Synthetic Genetic Array (SGA) and (ii) screening the double KO library in a selection of stress conditions. Data on large-scale functional analysis (i.e. bar-seq) and synthetic genetic interactions for the ncRNA collection will be presented: to date 27 ncRNAs mutants have been used as query strains for SGA and several gene interactions have been discovered showing either loss or gain in fitness.