Escherichia coli methionine-tRNAi/methionyl tRNA synthetase pairs induced protein initiation of interest (PII) expression

The precise regulatory role in protein synthesis by facilitating interactions with mRNA codons for various tRNA modifications is unclear. We previously reported that enhanced green fluorescent protein (GFP) reduced enhanced GFP mRNA expression in human methionine-conjugated initiator tRNA (tRNAi)/tRNA synthetase pairs under methionine-deficient conditions. Here, we investigated the effect of non-formylated methionine-conjugated Escherichia coli tRNAi on the synthesis of the protein initiation of interest (PII) in HeLa cells under intracellular L-methionine levels. We found that E. coli methionine-tRNAi counteracts human methionine-tRNAi, indicating that E. coli methionyl tRNA synthetase can induce enhanced GFP expression due to increased stability of enhanced GFP mRNA. Both complexes could support translation initiation without being employed to introduce methionine residues in the subsequent elongation steps. The results indicated that E. coli methionine-tRNAi could offset human methionine-tRNAi, and E. coli methionine-tRNAi/methionyl tRNA synthetase pairs can drive enhanced GFP mRNA expression. Unlike the human methionine-tRNAi/methionyl tRNA synthetase pairs that were used as a positive control, the non-formylated E. coli methionine-tRNAi/methionyl tRNA synthetase pairs reduced the expression of enhanced GFP mRNA, resulting in reduced HeLa cell survival. Using tRNAs functions causes of heterologous origin, such as from prokaryotes, and modified, to enhance or suppress the synthesis of specific proteins in eukaryotic organisms into the potential may possess a more prominent advantage of E. coli methionine-tRNAi as approaches that can control PII. This study provides new insights on the E. coli methionine- tRNAi/methionyl tRNA synthetase pair induced PII synthesis and the relative viability of cells could pave the way to regulate ecological/biological systems.