Difference between revisions of "Part:BBa K5398003"

Revision as of 09:19, 10 September 2024

The 3' intron of td gene from T4 phage

This part is a component of the td intron, an intron of the td gene from T4 phage belonging to group IE, which can form a circular mRNA (cmRNA) to make the ribosomes repeatedly translate the extron. This strategy can be used for expression of long peptides containing tandem repeats, like fibrous proteins.

The mechanism of cmRNA

Due to the special internal structure, the td intron can circularize the exon to form a back-splice junction (BSJ) in a reaction catalyzed by guanosine. To ensure that the ribosomes do not translate the ORF of gene of interest (GOI) from unprocessed linear mRNA, the ribosome binding sequence (RBS) and start codon ATG were placed downstream of GOI coding sequence. Consequently, the regulatory sequences were located upstream of the coding sequence only after circularization of the mRNA. To purify the resulting polypeptides, a His tag was incorporated into the GOI. If the mRNA is circularized, the ribosome could circle the cmRNA, producing a long repeating polypeptide (Fig. 2).

In our project, we used this part to design a cmRNA to produce the squid ring teeth proteins with five tandem repeats (TRn5).

Sequence and Features