Tzachi Pilpel (Weizmann Institute of Science)
Recent years have seen intensive progress in measuring protein
translation. However, the contributions of coding sequences to the
efficiency of the process remain unclear. Here, we identify a
universally conserved profile of translation efficiency along mRNAs
computed based on adaptation
between coding sequences and the tRNA pool. In this profile, the first
~30-50 codons are, on average, translated with a low efficiency.
Additionally, in eukaryotes, the last ~50 codons show the highest
efficiency over the full coding sequence. The profile predicts
accurately position-dependent ribosomal
density along yeast genes. These data suggest that translation speed,
and as a consequence, ribosomal density, are encoded by coding sequences
and the tRNA pool. We suggest that the slow "ramp" at the beginning of
mRNAs serves as a late stage of translation initiation, forming an
optimal and robust means to reduce ribosomal traffic jams, thus
minimizing the cost of protein expression.
Joint with Tamir Tuller, Asaf Carmi, Sivan Navon et al.
In Press in Cell 2010
Host: Zohar Yakhini