Rna Splicing
RNA splicing is a biological process where a newly synthesized pre-mRNA transcript is processed and transformed into mRNA. It involves the removal of non-coding regions of RNA (introns) and the joining of the coding regions (exons).
RNA Splicing is a process by which introns (non-coding regions) of a pre-mRNA molecule are removed and the remaining exons (coding regions) are joined together to form a mature mRNA molecule.
RNA splicing is the process by which the newly synthesized pre-mRNA, also known as hnRNA (heterogeneous nuclear RNA), is processed and converted to the mature mRNA. This post-transcriptional modification takes place in the nucleus and the mRNA then travels to the cytoplasm for translation or protein synthesis.
In prokaryotes such as bacteria, the newly transcribed RNA is ready for translation and both the processes can even occur simultaneously in the mRNA. Most of the eukaryotic genes are transcribed in the form of pre-mRNA and have to be processed before undergoing protein synthesis.
In the RNA splicing process, the non-coding intervening regions (i.e. introns) are removed and the coding regions (i.e. exons) are joined together. The process is catalysed by a spliceosome, and ribozymes (catalytic RNA) catalyse their own splicing.
Additionally, capping with a modified Guanine nucleotide at the 5’ end and tailing with Poly-A (Adenylate) residues at the 3’ end is also done to protect the coding segments and to provide stability to the mature mRNA.
RNA Splicing Process
In this process, introns are spliced out. RNA splicing is catalysed by spliceosomes, which is a protein-RNA complex, i.e. a complex of small nuclear ribonucleoproteins (snRNPs or snurps). It recognises and removes introns. Exons, which are the coding parts, are joined together.
Introns are removed at the specific sequences present at the 5’ and 3’ ends of the introns, known as splice sites.
Alternative Splicing
Alternative splicing is a process that increases the diversity of proteins by allowing RNAs to be spliced differently, resulting in different mRNA molecules that code for different proteins. This process is a normal splicing process in most eukaryotes.
Self-Splicing
Some genes, such as phage genes and protozoan ribosomal RNA genes, are capable of self-splicing, during which introns can catalyse their own excision from the parent RNA. Additionally, some mitochondrial genes are also capable of self-splicing.
The Significance of RNA Splicing
RNA splicing allows for the creation of multiple functional mRNAs from one transcript, which codes for various proteins.
It also helps in regulating gene expression and the protein content of the cell.
It helps in the evolution process by combining exons in different ways and creating new and better proteins.
New exons can be inserted into the introns to create new proteins without disrupting the functionality of the original gene.
Frequently Asked Questions
What are Spliceosomes?
Spliceosomes are molecular machines found in eukaryotic cells that are responsible for removing introns from pre-mRNA during the process of gene expression.
A spliceosome is typically composed of 5 snRNA molecules and a variety of associated proteins. This large RNP (ribonucleoprotein) complex is found in the eukaryotic nucleus and is also referred to as snRNPs or snurps.
The Phases Involved in Protein Synthesis Are:
- Transcription
- Translation
- Post-translational Modification
Protein synthesis is a biological process that involves the production of new proteins. This process consists of two phases: transcription and translation. In transcription, a portion of DNA coding for a protein is converted into an mRNA molecule. During translation, the mRNA molecule is decoded in a ribosome to produce the polypeptide chains.
Yes, proteins can undergo splicing.
Proteins, similar to RNA, can undergo splicing. During this process, the inteins are removed and the remaining exteins are joined together. This splicing has been observed in a variety of organisms, including archaea, bacteria, yeast, plants, and humans.
