TY  - JOUR
A1  - Bentele, Kajetan
A1  - Saffert, Paul
A1  - Rauscher, Robert
A1  - Ignatova, Zoya
A1  - Bluethgen, Nils
T1  - Efficient translation initiation dictates codon usage at gene start
JF  - Molecular systems biology
N2  - 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.
KW  - codon usage
KW  - mRNA structure
KW  - translation
Y1  - 2013
U6  - https://doi.org/10.1038/msb.2013.32
SN  - 1744-4292
VL  - 9
IS  - 6
PB  - Nature Publ. Group
CY  - New York
ER  -