What happens to the mRNA strand after it is handled by RISC?

The mRNA strand is degraded after being handled by RISC (RNA-induced silencing complex) due to the role that RISC plays in gene regulation. RISC is involved in the process of RNA interference (RNAi), where it typically associates with small RNA molecules, like microRNAs or small interfering RNAs (siRNAs).

Once RISC binds to a complementary mRNA target, it can either inhibit translation or lead to the degradation of that mRNA. The mechanisms of degradation involve the slicing of the mRNA strand into smaller fragments, rendering it unable to be translated into protein. This process is essential in controlling gene expression and maintaining cellular functions by preventing the production of specific proteins encoded by the target mRNA.

In this context, the other options do not accurately reflect the fate of the mRNA after RISC interaction. Reuse or rapid release does not occur; instead, the mRNA is effectively silenced through degradation. Translation is also not an outcome after RISC handling, as the purpose of RISC is to prevent the expression of genes by degrading the target mRNA rather than facilitating its translation.