Final answer:
Proteins bind to the 5' cap and poly(A) tail of mRNA to collaborate with the nuclear export receptor, facilitating the mRNA's export through the nuclear pore complex. Once in the cytoplasm, translation initiation factors take over for protein synthesis.
Step-by-step explanation:
The nuclear export of intact and unprocessed full-length mRNA in eukaryotic cells is facilitated by a complex of RNA-binding proteins and the nuclear export receptor. Specific proteins bind to the 5' methylguanosine cap and the poly(A) tail of the mRNA molecule. The cap-binding complex (CBC) interacts with the cap structure, while nuclear transport receptors such as mRNA export (Mex) factors or nuclear RNA export factors bind to the mature mRNA. Additionally, a poly-A-binding protein binds to the poly-A tail, ensuring the stability and regulatory compliance necessary for export through the nuclear pore complex. After the mRNA reaches the cytoplasm, translation initiation factors such as elF-4E replace the cap-binding proteins to commence protein synthesis.