Prokaryotic and Eukaryotic Transcription (Introduction)
Transcription is an important process for both eukaryotic as well as prokaryotic cells. But, does it apply to both? Well, it most certainly isn’t! There are tons of differences between prokaryotic and eukaryotic transpiration. These basic differences will do well to strengthen your concepts of prokaryotic and eukaryotic transcription, concerning one another. So, read the article below and get your concept right!
What is Prokaryotic and Eukaryotic Transcription?
To describe prokaryotic and eukaryotic transcription along with the differences among them, it is compulsory to understand them. Why? Because only by understanding them individually can we understand the differences between prokaryotic and eukaryotic transcription. So, keep reading to learn the characteristics of prokaryotic and eukaryotic transcription.
Prokaryotic Transcription
It is the process through which the genetic information of a prokaryotic organism in a cell is transcribed to RNA molecules. The initiation of prokaryotic transcription begins with the binding of RNA polymerase to the DNA template at the promoter region. Through it, by unwinding the DNA double helix using RNA polymerase, complementary RNA strands are synthesized. These are synthesised based on the nucleotide sequence of the DNA template. All this falls under the elongation part of transcription and terminates once a terminal signal is reached.
While being a process complex for prokaryotes, prokaryotic transcription has still got nothing close to the intricacies of eukaryotic transcription.
Eukaryotic Transcription
Eukaryotic Transcription is an important process in the conversion of genetic information from DNA to functional RNA molecules within eukaryotes. It takes place in three primary steps: initiation, elongation, and termination. And all these occur in a eukaryotic cell’s nucleus. The enzyme that helps out in this process in eukaryotes is RNA polymerase II. It does this by recognizing promoters-specific DNA sequences. Besides this, the transcription factors aid in proper initiation by recruiting RNA polymerase for initiation.
The RNA molecule post-transcription is maintained in its functionality and stability due to RNA splicing, and capping. It is another aspect that makes eukaryotic transcription different from prokaryotic transcription.
Difference between Prokaryotic and Eukaryotic Transcription
Do you always wonder about the prokaryotic and eukaryotic transcription difference? Then the table below will cover all your doubts regarding the prokaryotic and eukaryotic transcription- differences:
|
S. No. |
Category |
Procaryotic Transcription |
Eukaryotic Transcription |
| 1 | Location | Occurs in the cytoplasm | Occurs in the nucleus |
| 2 | DNA Complexity | Single circular chromosome | Multiple linear chromosomes |
| 3 | Transcription Machinery | RNA polymerase and sigma factor | RNA polymerase and transcription factors |
| 4 | Promoter Recognition | Recognise specific DNA sequences (consensus sequences) | Recognise core promoter elements, enhancers, and other regulatory elements |
| 5 | Enzymes | RNA Polymerases I, II, III | Single RNA Polymerase |
| 6 | Transcription Start Site | Often lacks a defined start site | Has a defined start site (TATA box or initiator element) |
| 7 | Number of polypeptides | Five | Ten to Fifteen |
| 8 | Transcription Termination | Usually involves a hairpin loop followed by a string of uracil (U) bases | Involves cleavage and polyadenylation of the pre-mRNA |
| 9 | Transcriptional Units | Operons are common | Operons are rare or absent |
| 10 | Transcription Factors | Few transcription factors involved | Multiple transcription factors involved |
| 11 | RNA Processing | Minimal processing of mRNA | Extensive processing of mRNA |
| 12 | Splicing | Generally no introns or splicing | Introns are common and undergo splicing |
| 13 | RNA Stability | mRNA is generally less stable | mRNA is more stable |
| 14 | mRNA Export | Can be translated immediately | Requires processing and export to the cytoplasm |
| 15 | Translation Coupling | Transcription and translation occur simultaneously | Transcription and translation are spatially separated |
| 16 | Post Transcriptional Regulation | Limited regulatory mechanisms | Extensive regulatory mechanisms (e.g., alternative splicing, RNA editing) |
| 17 | Transcription Rate | Generally higher | Generally lower |
| 18 | Complexity Control | Few regulatory mechanisms | Extensive regulatory mechanisms |
Similar Characteristics of Prokaryotic and Eukaryotic Transcription
Although there are the significant differences between eukaryotic and prokaryotic transcription processes, there are also some notable similarities:
- Initiation: At the initiation of transcription, both in eukaryotic and prokaryotic transcription, specific DNA sequences are recognized. Even though the sigma factor aids in the binding process at the promoter region in prokaryotes, transcription factors assist the process in the recognition of the promoter in eukaryotes.
- Elongation: Synthesis of RNA in elongation both in eukaryotic and prokaryotic transcription involves the movement of the RNA polymerase along the DNA template strand where it adds nucleotides to the growing RNA molecule.
- Termination: The transcription of both prokaryotes and eukaryotes terminate by specific signals. Prokaryotes generally have two termination mechanisms; rho-dependent termination where the rho protein can act as a facilitator for termination, and rho-independent termination, that involves particular DNA sequences. Eukaryotes utilize the polyadenylation signals and termination factors to cause termination of the transcription.
- RNA Processing: In prokaryotes and eukaryotes, newly synthesized RNA molecules are processed. mRNA in prokaryotes can be directly used for translation. However, in eukaryotes, mRNA after synthesis has to undergo some processing steps by RNA splicing of removing introns, addition of 5′ cap, and addition of poly A tail.
Conclusion
After reading this article, you will never have a doubt concerning how prokaryotic and eukaryotic transcription differ. And it’s not only that. You will now be able to explain how prokaryotic and eukaryotic transcription differ and which is categorically different. That’s not all! This article also guides you on the similarities that both prokaryotic and eukaryotic transcription share. Therefore, it is the perfect guide for relating between the prokaryotic and the eukaryotic transcription.
