Team:Wisconsin-Madison/SDF

• Team

  • Team Members
  • Advisors
  • Sponsors

• Projects

  • Engineering Limonene Production in E.coli
  • Translational Coupling Cassette (TCC)

• Parts

  • Translational Coupling Cassette
  • Negative TCC Control
  • Positive TCC Control
  • Codon-optomized LIMS1

• Modeling

• Protocol

• Safety

• Human practice

Translational Coupling – an explanation

Translational coupling is a phenomena discovered after researchers observed that the translation efficiency of a gene is effected by the translation efficiency an upstream gene (towards the 5’ end) of the same mRNA. (adhya and gottesman 1978).

This relationship is the result of a competition between ribosomes and rho factors for access to the mRNA. (Oppenheim and Yanofsky 1980) For a gene with high translational efficiency, ribosomes will crowd the mRNA strand, preventing rho from degrading it. Conversely, for a gene with low translational efficiency, parts of the mRNA strand will be bare, allowing rho easy access to quickly degrade the nucleotide. (fig 1)

Secondary structure of the mRNA can also play a factor in this competition. If the RBS site is part of a hairpin structure, ribosomes will be unable to bind to the mRNA strand. (fig 2) This will allow rho to quickly degrade the strand, thus lowering the translational efficiency of all genes on that mRNA. However, if a downstream gene’s RBS is close to the upstream gene’s stop codon, the helicase activity of the upstream ribosomes will linearize any secondary structure that locks up the downstream RBS. (fig 3)