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Schikora Tamarit, M. A.

Publications and source records attributed to Schikora Tamarit, M. A..

2 recordsLinked to original sources

Poor codon optimality is a signal to degrade transcripts with frameshifts

Living organisms are error-prone. Every second a single human cell produces over 100 transcripts with a substitution, frameshift or splicing error. Multiple mRNA quality control pathways exist to degrade these transcripts. Many of these pathways involve co-translational regulation of mRNA stability, such as nonsense mediated decay (NMD) and reduced stability of transcripts with suboptimal codon usage. Recent work has shown the existence of a genetic link between NMD and codon-usage mediated mRNA decay. Here we present new computational evidence that, because the codons following most frameshift errors are suboptimal, removal of mRNAs with such errors may be mediated by degradation of mRNAs with sub-optimal codons. Thus, most transcripts that contain frameshifts are subject to two modes of degradation.\n\nAuthor summaryFrameshifting errors are common and mRNA quality control pathways, such as nonsense-mediated decay (NMD), exist to degrade these aberrant transcripts. Recent work has shown the existence of a genetic link between NMD and codon-usage mediated mRNA decay. Here we present computational evidence that these pathways are synergic for removing frameshifts.

genomics

Promoter architecture determines co-translational regulation of mRNA

Information that regulates gene expression is encoded throughout each gene but if different regulatory regions can be understood in isolation, or if they interact, is unknown. Here we measure mRNA levels for 10,000 open reading frames (ORFs) transcribed from either an inducible or constitutive promoter. We find that the strength of co-translational regulation on mRNA levels is determined by promoter architecture. Using a novel computational-genetic screen of 6402 RNA-seq experiments we identify the RNA helicase Dbp2 as the mechanism by which co-translational regulation is reduced specifically for inducible promoters. Finally, we find that for constitutive genes, but not inducible genes, most of the information encoding regulation of mRNA levels in response to changes in growth rate is encoded in the ORF and not in the promoter. Thus the ORF sequence is a major regulator of gene expression, and a non-linear interaction between promoters and ORFs determines mRNA levels.

systems biology