Related Experiment Videos
The genomic pattern of tDNA operon expression in E. coli
David H Ardell1, Leif A Kirsebom
1Department of Cell and Molecular Biology, Biomedical Center, Uppsala University, Uppsala, Sweden. dave.ardell@lcb.uu.se
Plos Computational Biology
|August 17, 2005
Summary
Bacterial translational streamlining, optimizing growth rate, is largely independent of growth rate. Operon organization and genomic location significantly influence transfer RNA (tRNA) expression, suggesting selection for high-growth demands.
Area of Science:
- Microbiology
- Molecular Biology
- Genomics
Background:
- Fast-growing microorganisms exhibit biased transfer RNA (tRNA) isoacceptor usage, optimizing translational efficiency and minimizing cellular mass.
- This translational streamlining is hypothesized to be growth-regulated, but the underlying genetic mechanisms remain unclear.
Purpose of the Study:
- To investigate the genetic basis of translational streamlining in *E. coli*.
- To determine the influence of tRNA operon organization and genomic location on tRNA expression profiles.
Main Methods:
- Reanalysis of *E. coli* tRNA profiles across different growth rates.
- Least squares multiple regression to partition tRNA isoacceptor pools to predicted tDNA operons.
- Analysis of tDNA operon expression in relation to proximity to the origin of replication (oriC) and genomic strand.
Main Results:
- The degree of translational streamlining in *E. coli* is nearly invariant with growth rate.
- Co-expression within tDNA operons better explains the tRNA profile than gene dosage alone.
- Operon expression correlates with proximity to oriC, with distinct patterns on leading and lagging strands.
Conclusions:
- Operonic organization and genomic location are significant determinants of tRNA expression.
- Nonrandom genomic architecture of tDNA operons suggests selection to meet tRNA demands at high growth rates.