Chemically Acylated tRNAs are Functional in Zebrafish Embryos

Area of Science:

• Biochemistry
• Molecular Biology
• Developmental Biology

Background:

• Genetic code expansion enables the creation of proteins with non-canonical amino acids.
• Engineered aminoacyl tRNA synthetases are key to incorporating novel amino acids.
• Limitations exist in synthetase capacity for accommodating large or complex unnatural amino acid side chains.

Purpose of the Study:

• To establish a robust method for site-specific unnatural amino acid incorporation in zebrafish embryos.
• To overcome the limitations of engineered synthetases in accommodating specific unnatural amino acids.
• To demonstrate optical control of enzyme activity in vivo using photocaged amino acids.

Main Methods:

• Utilized chemical acylation of tRNAs for site-specific unnatural amino acid incorporation.
• Applied this method in zebrafish embryos, a model organism for human health.
• Incorporated a photocaged histidine analogue that is challenging for synthetase engineering.

Main Results:

• Achieved robust and site-specific incorporation of unnatural amino acids into zebrafish proteins.
• Successfully incorporated a photocaged histidine analogue, overcoming prior synthetase engineering challenges.
• Demonstrated optical control of enzyme activity in live zebrafish embryos by incorporating the photocaged histidine.

Conclusions:

• Chemical tRNA acylation provides a powerful alternative for genetic code expansion, especially for challenging amino acids.
• This approach expands the toolkit for creating novel proteins with tailored functions in vivo.
• The method enables precise spatiotemporal control of biological processes in a complex model organism.