Question

Describe post-transcriptional processing of RNA in eukaryotes.

Answer 1

Hint: To deduce an answer, we must first understand the typical meaning of post-transcriptional modifications. By the word post, we can understand that there are modifications that occur after the process of transcription in eukaryotic cells.

Complete answer:
Post-transcriptional modifications are those modifications that occur in the RNA transcript after transcription that leads to the formation of mature RNA so that it is able to carry out all its function in the cell.
The first process that occurs is capping. Here a 7-methylguanosine is added to the 5' end.
The second process that occurs is the 3' processing. Here, the 3' end of RNA is cleaved and about 250 adenine residues are added to form the poly-A tail.
After this step comes the process of intron splicing. Here the introns are removed so that the exons can join to form a continuous linear structure. Introns are those parts that do not code for any proteins. Histone mRNA processing also occurs.
Processing of core histones is done differently because typical histone mRNA lacks several features of other eukaryotic mRNAs, such as poly(A) tail and introns. However, in the case of histone variants such as H3.3 are processed in a similar manner to normal mRNA that includes the process of splicing and formation of poly-A tail.

Note: Post-transcriptional modifications are of immense importance because it helps RNA recognition by molecules involved in translation. Moreover, it also leads to the removal of those parts that are not required to be translated to form functional proteins.