A) stability of RNA only
   B) transport of RNA only
   C) stability and transport of RNA
   D) methylation of RNA only
   E) none of these
 Ans: C) stability and transport of RNA
         5' capping: A key step in RNA processing |
- After transcription, the phosphate group at the 5' end is removed and replaced by a guanine residue by guanosyl transferase and further methylated to form 7-methyl guanosine cap (m7G).
- 5' cap protects the 5' end of mRNA against ribonuclease degradation and also functions in protein synthesis initiation.
- This stabilizes pre -mRNA and is important for the stability of mature mRNA. It also important in binding to the nuclear matrix and transport of mRNA out of the nucleus.