<tr><td style="padding: 5px 0px 5px 20px; width: 750px; vertical-align: top;" colspan="9"> Generally, mRNA is single-strand RNA, starting translation by binding ribosome on initiation codon, and ending by separating ribosome from mRNA. In this study, we aim to build the method of synthesizing long-repeating proteins, massive　one, and to improve translation efficiency. That is, allowing ribosomes to have a semi-permanent translation mechanism by producing circular mRNA and causing a defect of termination codon. To cyclize mRNA, we can use a splicing mechanism of T4 phage. Splicing is a mechanism removing circular introns and joining in exons after transcription. Splicing is catalyzed by several base sequences at both ends of intron as a ribozyme, being subjected to nucleophilic attack from introns to exons. We would like to clone the two parts of intron to use this mechanism and cyclize mRNA, making plasmids which include a gene coding proteins between those. And, by transforming E.coli, we get world’s longest proteins.