What is the primary function of RNA capping?

The primary function of RNA capping is the addition of a modified guanine nucleotide to the 5' end of pre-mRNA. This process is essential for several reasons. Firstly, the 5' cap protects the mRNA from degradation by exonucleases, which could otherwise rapidly degrade the RNA before it is translated into a protein. Secondly, the cap structure plays a critical role in the initiation of translation by facilitating the recognition of the mRNA by the ribosome. This capping also aids in the proper splicing of pre-mRNA and contributes to the export of the mRNA from the nucleus to the cytoplasm. Overall, capping is a vital modification that enhances the stability and translatability of mRNA, ensuring that the genetic information encoded can be efficiently utilized by the cell.