mRNA, after its synthesis, migrates from the nucleus to the ribosomes in the cytoplasm. This is where translation takes place, and the mRNA sequence is used to build a protein.

Here's a breakdown of the process:

1. Transcription: DNA is transcribed into mRNA in the nucleus.

2. Processing: The mRNA undergoes processing, including capping, splicing, and polyadenylation.

3. Export: The mature mRNA is transported out of the nucleus and into the cytoplasm.

4. Translation: The mRNA associates with ribosomes, which read the mRNA sequence and use it to assemble amino acids into a protein chain.

So, to answer your question directly: mRNA migrates from its site of synthesis and becomes attached to ribosomes.