[gas_dr]

After translation, mRNA is naturally broken down. It is not there indefinitely. There is a proteolytic cleaving process for translated mRNA.

[Grandpa Drudge]

Readers of this thread deserve a single answer to your irrelevant comment for clarity, simply to avoid confusion.

mRNA is the messenger, and what happens to it once the message is delivered is likely unimportant. The message is used to produce something that is designed and intended to remain indefinitely, if not permanently.