Differential RNA Splicing (Alternative Splicing)in Eukaryotes; Post Transcriptional Modifications
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Alternative Splicing in Eukaryotes
- There is a mechanism in Eukaryotes that is called Alternative Splicing,
- It is also called Differential RNA Splicing.
- It should NOT be confused with Polycistronic messages.
- Polycistronic messages are specific in Prokaryotes.
- In Alternative splicing a single mRNA molecule that is produced from a DNA template and has a number o f Exons present in it as well as a certain number of Introns.
- Remember the key maturation steps were:
- The Capping
- Polyadenylation and
- In certain cell types the splicing occurs in different ways.
- For example in one of the cell types certain Exons get together while in other cell type, the other Exons get together.
- This process in known as Alternative Splicing.
- By this process a greater number of proteins can be produced by the genes which are much smaller in number as compared to the proteins produced by them.
- This diversity is only possible due to alternative splicing.
Alternative Splicing Process
- In Alternative splicing there is one single mRNA
- For this single mRNA, there is one start and one stop codon, unlike in Polycistronic messages in Prokaryotes.
- The ribosome comes and starts at the start codon and ends at the stop codon.
- But prior to this translation by the ribosome, there will be some splicing.
- The variations in splicing are shown in the figure along with this lesson.
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