@article{BartholomaeusFedyuninFeistetal.2016,
  author    = {Bartholom{\"a}us, Alexander and Fedyunin, Ivan and Feist, Peter and Sin, Celine and Zhang, Gong and Valleriani, Angelo and Ignatova, Zoya},
  title     = {Bacteria differently regulate mRNA abundance to specifically respond to various stresses},
  series = {Geology},
  volume    = {374},
  journal   = {Geology},
  publisher = {Royal Society},
  address   = {London},
  issn      = {1364-503X},
  doi       = {10.1098/rsta.2015.0069},
  pages     = {16},
  year      = {2016},
  abstract  = {Environmental stress is detrimental to cell viability and requires an adequate reprogramming of cellular activities to maximize cell survival. We present a global analysis of the response of Escherichia coli to acute heat and osmotic stress. We combine deep sequencing of total mRNA and ribosome-protected fragments to provide a genome-wide map of the stress response at transcriptional and translational levels. For each type of stress, we observe a unique subset of genes that shape the stress-specific response. Upon temperature upshift, mRNAs with reduced folding stability up-and downstream of the start codon, and thus with more accessible initiation regions, are translationally favoured. Conversely, osmotic upshift causes a global reduction of highly translated transcripts with high copy numbers, allowing reallocation of translation resources to not degraded and newly synthesized mRNAs.},
  language  = {en}
}
@article{BenteleSaffertRauscheretal.2013,
  author    = {Bentele, Kajetan and Saffert, Paul and Rauscher, Robert and Ignatova, Zoya and Bluethgen, Nils},
  title     = {Efficient translation initiation dictates codon usage at gene start},
  series = {Molecular systems biology},
  volume    = {9},
  journal   = {Molecular systems biology},
  number    = {6},
  publisher = {Nature Publ. Group},
  address   = {New York},
  issn      = {1744-4292},
  doi       = {10.1038/msb.2013.32},
  pages     = {10},
  year      = {2013},
  abstract  = {The genetic code is degenerate; thus, protein evolution does not uniquely determine the coding sequence. One of the puzzles in evolutionary genetics is therefore to uncover evolutionary driving forces that result in specific codon choice. In many bacteria, the first 5-10 codons of protein-coding genes are often codons that are less frequently used in the rest of the genome, an effect that has been argued to arise from selection for slowed early elongation to reduce ribosome traffic jams. However, genome analysis across many species has demonstrated that the region shows reduced mRNA folding consistent with pressure for efficient translation initiation. This raises the possibility that unusual codon usage is a side effect of selection for reduced mRNA structure. Here we discriminate between these two competing hypotheses, and show that in bacteria selection favours codons that reduce mRNA folding around the translation start, regardless of whether these codons are frequent or rare. Experiments confirm that primarily mRNA structure, and not codon usage, at the beginning of genes determines the translation rate.},
  language  = {en}
}
@article{GorochowskiAycilarKucukgozeBovenbergetal.2016,
  author    = {Gorochowski, Thomas E. and Aycilar-Kucukgoze, Irem and Bovenberg, Roel A. L. and Roubos, Johannes A. and Ignatova, Zoya},
  title     = {A Minimal Model of Ribosome Allocation Dynamics Captures Trade-offs in Expression between Endogenous and Synthetic Genes},
  series = {ACS synthetic biology},
  volume    = {5},
  journal   = {ACS synthetic biology},
  publisher = {American Chemical Society},
  address   = {Washington},
  issn      = {2161-5063},
  doi       = {10.1021/acssynbio.6b00040},
  pages     = {710 -- 720},
  year      = {2016},
  abstract  = {Cells contain a finite set of resources that must be distributed across many processes to ensure survival. Among them, the largest proportion of cellular resources is dedicated to protein translation. Synthetic biology often exploits these resources in executing orthogonal genetic circuits, yet the burden this places on the cell is rarely considered. Here, we develop a minimal model of ribosome allocation dynamics capturing the demands on translation when expressing a synthetic construct together with endogenous genes required for the maintenance of cell physiology. Critically, it contains three key variables related to design parameters of the synthetic construct covering transcript abundance, translation initiation rate, and elongation time. We show that model-predicted changes in ribosome allocation closely match experimental shifts in synthetic protein expression rate and cellular growth. Intriguingly, the model is also able to accurately infer transcript levels and translation times after further exposure to additional ambient stress. Our results demonstrate that a simple model of resource allocation faithfully captures the redistribution of protein synthesis resources when faced with the burden of synthetic gene expression and environmental stress. The tractable nature of the model makes it a versatile tool for exploring the guiding principles of efficient heterologous expression and the indirect interactions that can arise between synthetic circuits and their host chassis because of competition for shared translational resources.},
  language  = {en}
}
@article{SaffertAdamlaSchiewecketal.2016,
  author    = {Saffert, Paul and Adamla, Frauke and Schieweck, Rico and Atkins, John F. and Ignatova, Zoya},
  title     = {An Expanded CAG Repeat in Huntingtin Causes+1 Frameshifting},
  series = {The journal of biological chemistry},
  volume    = {291},
  journal   = {The journal of biological chemistry},
  publisher = {American Society for Biochemistry and Molecular Biology},
  address   = {Bethesda},
  issn      = {0021-9258},
  doi       = {10.1074/jbc.M116.744326},
  pages     = {18505 -- 18513},
  year      = {2016},
  abstract  = {Maintenance of triplet decoding is crucial for the expression of functional protein because deviations either into the -1 or +1 reading frames are often non-functional. We report here that expression of huntingtin (Htt) exon 1 with expanded CAG repeats, implicated in Huntington pathology, undergoes a sporadic +1 frameshift to generate from the CAG repeat a trans-frame AGC repeat-encoded product. This +1 recoding is exclusively detected in pathological Htt variants, i.e. those with expanded repeats with more than 35 consecutive CAG codons. An atypical +1 shift site, UUC C at the 5 end of CAG repeats, which has some resemblance to the influenza A virus shift site, triggers the +1 frameshifting and is enhanced by the increased propensity of the expanded CAG repeats to form a stem-loop structure. The +1 trans-frame-encoded product can directly influence the aggregation of the parental Htt exon 1.},
  language  = {en}
}