In vitro, free oligonucleotides, such as mRNA transcripts, have a short half-life in the cytosol. What mechanism is used to stabilize these molecules? A.PolyadenylationB.PhosphorylationC.Enzymatic digestionD.Active transport across the nuclear membrane

The mechanism used to stabilize mRNA transcripts in the cytosol is A. Polyadenylation.

Here's a step-by-step explanation:

1. Transcription: The process begins in the nucleus where the DNA is transcribed into pre-mRNA.

2. Pre-mRNA Processing: The pre-mRNA undergoes several modifications. One of these is the addition of a poly(A) tail at the 3' end of the transcript, a process known as polyadenylation.

3. Polyadenylation: This process involves the addition of a series of adenine (A) nucleotides to the end of the pre-mRNA molecule. This poly(A) tail protects the mRNA from degradation, aids in the export of the mature mRNA to the cytoplasm, and is involved in binding proteins involved in initiating translation.

4. mRNA Export: The mature mRNA is then transported out of the nucleus and into the cytoplasm where it can be translated into a protein.

So, the correct answer is A. Polyadenylation.