How prokaryotic and eukaryotic transcription differ from each other?
Eukaryotic and prokaryotic transcription differs in many aspects, which are discussed below:
Types of polymerases:
There are three types of RNA polymerases for gene transcription in eukaryotic cells,RNA polymerase l, ll, lll.
Whereas there is only one type of RNA polymerase enzymes for gene transcription in prokaryotic cell.
Monocistronic and Polycistronic characteristics:
The mRNA carries information from just one gene in eukaryotes, and it is said to be monocistronic characteristic of eukaryotes.
While prokaryotes have polycistronic characteristic,the mRNA carries information from more than one gene.
Structural characteristic of mRNA:
In eukaryotes special structural characteristic of mRNA include a"poly-A tail" on the 3' end of the RNA chain plus a "cap" on the 5' end.
On the other hand no such structures are present in prokaryotes.
Initiation Complex:
Transcription begins with the formation of initiation complex, which includes different TBP, Transcription factors, RNA Polymerases and many complexes bind atthe Promoter region in eukaryotes.
While in prokaryotes transcription begins with the binding of RNA polymerase holoenzyme to the promoter region
Elongation coupled to RNA processing:
In eukaryotes the mRNA prepares it self to start its journey into cytoplasm by capping, splicing and polyadenylation steps.
And in prokaryotes, there are no such steps included with elongation, as the RNA does not require to travel into cytoplasm.
Termination signal:
In eukaryotes, termination is dictated by a terminator sequence and poly-A signal, which terminates the gene transcription .
Prokaryotic termination is relatively simple with only two different mechanism Rho dependent and Rho independent.
