Using a quadruplet codon to expand the genetic code of an animal

Area of Science:

• Synthetic Biology
• Molecular Biology
• Genetics

Background:

• Genetic code expansion in multicellular organisms typically relies on amber stop codons.
• Existing methods face limitations in efficiency and scope for in vivo applications.

Purpose of the Study:

• To establish a novel system for genetic code expansion in multicellular organisms using quadruplet codons.
• To demonstrate the in vivo incorporation of non-canonical amino acids (ncAAs) in Caenorhabditis elegans.
• To enable optogenetic control of cellular functions through ncAA incorporation.

Main Methods:

• Development of hybrid pyrrolysyl-tRNA variants for quadruplet codon decoding.
• Utilizing the UAGA quadruplet codon for specific ncAA incorporation.
• Incorporation of photocaged amino acids into Cre recombinase and caspase proteins.

Main Results:

• Successful in vivo incorporation of ncAAs in response to the UAGA quadruplet codon in C. elegans.
• Demonstrated functional expression of photocaged Cre recombinase for optical gene expression control.
• Showcased photo-activatable caspase for light-inducible cell ablation, validating the system's utility.

Conclusions:

• The developed quadruplet decoding system offers a powerful new tool for genetic code expansion in eukaryotes.
• This approach overcomes limitations of existing methods, facilitating broader adoption in multicellular organisms.
• Enables precise control over gene expression and cellular processes using light-activated proteins.