Engineering bacterial translation initiation - Do we have all the tools we need?
Reliable tools that allow precise and predictable control over gene expression are critical for the success of nearly all bioengineering applications. Translation initiation is the most regulated phase during protein biosynthesis, and is therefore a promising target for exerting control over gene expression. At the translational level, the copy number of a protein can be fine-tuned by altering the interaction between the translation initiation region of an mRNA and the ribosome. These interactions can be controlled by modulating the mRNA structure using numerous approaches, including small molecule ligands, RNAs, or RNA-binding proteins. A variety of naturally occurring regulatory elements have been repurposed, facilitating advances in synthetic gene regulation strategies. The pursuit of a comprehensive understanding of mechanisms governing translation initiation provides the framework for future engineering efforts.



Here we outline state-of-the-art strategies used to predictably control translation initiation in bacteria. We also discuss current limitations in the field and future goals.



Due to its function as the rate-determining step, initiation is the ideal point to exert effective translation regulation. Several engineering tools are currently available to rationally design the initiation characteristics of synthetic mRNAs. However, improvements are required to increase the predictability, effectiveness, and portability of these tools.



Predictable and reliable control over translation initiation will allow greater predictability when designing, constructing, and testing genetic circuits. The ability to build more complex circuits predictably will advance synthetic biology and contribute to our fundamental understanding of the underlying principles of these processes. "This article is part of a Special Issue entitled "Biochemistry of Synthetic Biology - Recent Developments" Guest Editor: Dr. Ilka Heinemann and Dr. Patrick O'Donoghue.
Alberta RNA Research and Training Institute, Department of Chemistry and Biochemistry, University of Lethbridge, 4401 University Drive West, Lethbridge, Alberta T1K 3M4, Canada.
Justin R J
JRJ
Vigar
Alberta RNA Research and Training Institute, Department of Chemistry and Biochemistry, University of Lethbridge, 4401 University Drive West, Lethbridge, Alberta T1K 3M4, Canada. Electronic address: hj.wieden@uleth.ca.
Hans-Joachim
HJ
Wieden
D001419:Bacteria / Q000235:genetics* / Q000378:metabolism*; D018387:Codon, Initiator / Q000235:genetics* / Q000378:metabolism; D004926:Escherichia coli; D015964:Gene Expression Regulation, Bacterial; D010442:Peptide Chain Initiation, Translational / Q000235:genetics*; D014176:Protein Biosynthesis / Q000235:genetics; D015202:Protein Engineering / Q000379:methods*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D012270:Ribosomes / Q000378:metabolism
D018387:Codon, Initiator; D012333:RNA, Messenger
RNA engineering; Rational design; Riboregulation; Ribosome engineering; Synthetic biology; Translation initiation