What must not remain bound when the ribosome reaches the stop codon during translation?

During the process of translation, when the ribosome encounters a stop codon, it signals the termination of protein synthesis. At this point, the ribosome will recruit release factors that promote the disassembly of the translation complex. This involves the release of the newly synthesized polypeptide chain from the tRNA in the P site and ultimately leads to the disassembly of the ribosome from the mRNA and associated factors.

The Exon Junction Complex (EJC) is a protein complex that marks the boundaries of exons in mRNA and is important for mRNA stability and the regulation of translation. However, during the termination of translation, it is essential for EJC components to be released, as they are no longer needed once the ribosome has completed translation. If they remain bound, they could interfere with subsequent recycling of the mRNA or the assembly of the next translation complex.

In contrast, while the Poly-A tail and mRNA itself are crucial for translation initiation and stability, they do not necessarily need to be released at the termination stage, nor do initiation factors that are used earlier in the translation process need to stay attached or be removed specifically during this step. Thus, the correct focus is on the need for the Exon Junction Complex to