TY  - JOUR
A1  - Avcilar-Kucukgoze, Irem
A1  - Bartholomäus, Alexander
A1  - Varela, Juan A. Cordero
A1  - Kaml, Robert Franz-Xaver
A1  - Neubauer, Peter
A1  - Budisa, Nediljko
A1  - Ignatova, Zoya
T1  - Discharging tRNAs: a tug of war between translation and detoxification in Escherichia coli
JF  - Nucleic acids research
N2  - Translation is a central cellular process and is optimized for speed and fidelity. The speed of translation of a single codon depends on the concentration of aminoacyl-tRNAs. Here, we used microarray-based approaches to analyze the charging levels of tRNAs in Escherichia coli growing at different growth rates. Strikingly, we observed a non-uniform aminoacylation of tRNAs in complex media. In contrast, in minimal medium, the level of aminoacyl-tRNAs is more uniform and rises to approximately 60%. Particularly, the charging level of tRNA(Ser), tRNA(Cys), tRNA(Thr) and tRNA(His) is below 50% in complex medium and their aminoacylation levels mirror the degree that amino acids inhibit growth when individually added to minimal medium. Serine is among the most toxic amino acids for bacteria and tRNAs(Ser) exhibit the lowest charging levels, below 10%, at high growth rate although intracellular serine concentration is plentiful. As a result some serine codons are among the most slowly translated codons. A large fraction of the serine is most likely degraded by L-serine-deaminase, which competes with the seryl-tRNA-synthetase that charges the tRNAs(Ser). These results indicate that the level of aminoacylation in complex media might be a competition between charging for translation and degradation of amino acids that inhibit growth.
Y1  - 2016
U6  - https://doi.org/10.1093/nar/gkw697
SN  - 0305-1048
SN  - 1362-4962
VL  - 44
SP  - 8324
EP  - 8334
PB  - Oxford Univ. Press
CY  - Oxford
ER  - 
TY  - JOUR
A1  - Bartholomäus, Alexander
A1  - Fedyunin, Ivan
A1  - Feist, Peter
A1  - Sin, Celine
A1  - Zhang, Gong
A1  - Valleriani, Angelo
A1  - Ignatova, Zoya
T1  - Bacteria differently regulate mRNA abundance to specifically respond to various stresses
JF  - Geology
N2  - 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.
KW  - transcription
KW  - translation
KW  - deep sequencing
KW  - Escherichia coli
KW  - copy numbers
Y1  - 2016
U6  - https://doi.org/10.1098/rsta.2015.0069
SN  - 1364-503X
SN  - 1471-2962
VL  - 374
PB  - Royal Society
CY  - London
ER  - 
TY  - THES
A1  - Bartholomäus, Alexander
T1  - Analyzing Transcriptional and Translational Control in E. coli using Deep-Seq Data
Y1  - 2016
ER  -