An Artemia salina factor which counteracts the mRNA-induced inhibition of initiator Met-tRNA binding to initiation factor eIF-2.

Ternary complex formation between eukaryotic initiation factor 2 (eIF-2), initiator Met-tRNA and guanosine 5′-(β, γ-imino) triphosphate [GMP-P(NH)P] is strongly inhibited by mRNA in the $\text{Artemia salina}$ system. Developing $\text{A. salina}$ embryos contain a factor which displays a novel activity, namely the ability to counteract the mRNA-induced inhibition of ternary complex formation. This factor is heat-labile. It is proposed that the factor may play an important role in protein biosynthesis by preventing mRNA from inhibiting an early step of peptide chain initiation.