News came out on Wednesday, August 9, 2023, that Alltrna has successfully raised $109M in Series B round to continue its development on tRNA therapies. Founded in 2018 in Newton, Massachusetts, as a Flagship startup, Alltrna has so far raised a total of $159M over two rounds from Flagship. It emerged from stealth mode in 2021 with the first round of $50M in funding. There are currently about 65 employees at the startup company.
Alltrna is focused on the therapeutic applications of tRNA. Although the importance of tRNA has been recognized for decades for its role in translating messenger RNA into proteins, there has been very little progress in tRNA therapies due to the intrinsic complexity caused by their heavy modifications. The sequencing and synthesis of tRNA are also challenging due to these modifications. Alltrna claims to be the first company to successfully synthesize tRNA through chemical reactions. Specific indications haven’t been revealed yet, but Alltrna claims that engineered tRNA has the potential to treat common and rare diseases caused by unexpected “stop codons” from genetic mutations and insert the correct amino acid during translation.
tRNAs are generally 76-90 nucleotides long, with their secondary structure and tertiary structure shown in Figure 1. (a) shows the cloverleaf secondary structure, and (b) is the 3D “L”-shaped tertiary structure of tRNA. tRNA plays a vital role in protein expression. After DNA encoding protein has been transcribed into mRNA, mRNA is transported out of the nucleus, binds onto the ribosomes in the cytoplasm, and starts the translation process. The coding sequence of mRNA is composed of units known as “codons,” trios of letters that are translated to specific amino acids. During translation, as the mRNA coding sequence is being read by the ribosome, tRNAs carry over the amino acids, bind to the ribosome, and add the amino acids to the growing peptide chain that will eventually form a complete protein.
Later posts will provide further information on tRNA structure, functionality, and therapeutic applications.
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