DISCUSSION FORUM


USER QUERY
GAURI Sharma
2020-05-01
An eukaryotic cell undergoing mRNA
synthesis and processing was incubated with
32P labelled ATP, with the label at the beta-
position. Where do you think the radioactive
isotope will appear in the mature mRNA?
1. 32P will not appear in the mature mRNA
under any circumstances because beta and gamma
phosphates are released during
transcription.
2. Phosphate groups of the phoshodiester
backbone of the mRNA will be uniformly
labelled as only alpha phosphates are released
during transcription.
3. 32P will appear at the 5' end of the mRNA if
only it has ?A? as the first nucleotide.
4. No 32P will appear in the mature mRNA
because the 5'-terminal phosphate of an
?A? residue will be further removed during
the capping process.