Protein biogenesis in Archaea: addressing translation initiation using an in vitro protein synthesis system for Haloferax volcanii.

Translation initiation in Archaea combines aspects of the parallel process in Eukarya and Bacteria alongside traits unique to this domain. To better understand translation initiation in Archaea, an in vitro translation system from the haloarchaeon Haloferax volcanii has been developed. The ability to translate individual mRNAs both under the conditions used in previously developed poly(U)-dependent poly(Phe) synthesis systems as well as under physiological conditions was shown. Using the H. volcanii system, mRNAs proceeded by either 'strong' or 'weak' Shine-Dalgarno (SD) motifs, or completely lacking leader sequences were effectively translated. The in vitro haloarchaeal system also successfully translated mRNA from Bacteria, again either presenting a SD initiation motif or completely lacking a leader sequence. Thus, the ability to translate individual mRNAs in vitro offers a system to address translation initiation as well as other aspects of protein biogenesis in Archaea.