Transcription in Eukaryotes

The structural genes in a transcription unit could be said as monocistronic (mostly in eukaryotes) or polycistronic (mostly in bacterias and prokaryotes).

The structural genes in eukaryotes are split into two regions:-

1. Exons – the regions or expressed sequences are defined as exons.

2. Introns– The region which do not code for proteins.

Due To The Presence Of Introns

Primary RNA – transcripts became non- functional.

RNA Splicing

In some genes the protein-coding sections of the DNA (“exons”) are interrupted by non-coding regions (“introns”). RNA splicing removes the introns from pre mRNA to produce the final set of instructions

Capping and Tailing Processes :-

Additional modifications to the 5′ and 3` ends of eukaryotic pre – MRNA.

Capping :-

• It is the addition of a cap on 1st nucleotide’s 5′ end of pre-mRNA.
• A 7-methylguanosine cap is added to the 5′ end.
• It is formed by metyl guanosine triphosphate.
• In addition, initiation factors involved in protein synthesis recognize the cap to help initiate translation by ribosomes.