Question

What is splicing?

Answer 1

Gene splicing plays an important role in human physiology and diseases. They lead to the synthesis of alternative proteins in the body. Splicing is a process in which introns are removed to produce mature messenger RNA that is generally composed of only exons.

Complete answer-
Gene splicing is a post- transcriptional modification in which a single gene codes for multiple proteins. It is mainly done in eukaryotes, prior to mRNA translation. It is done to extract protein diversity. In this process, the pre- mRNA transcribed from one gene can lead to different mature mRNA molecules to form functional proteins. Gene splicing enables a single gene to increase the coding capacity, helps in synthesis of protein isoforms which are structurally as well as functionally distinct from each other. In the human cell, around 40 to 60% of the gene exhibit alternative splicing.
Gene splicing mechanism: These events occur simultaneously in the gene after the mRNA is formed from the transcription in the central dogma of molecular biology.
EXON SKIPPING- This is the most common method for gene splicing where exon may or may not be included in the final gene transcript leading to extension or shortening of mRNA variants. We all know that exons are the coding region of a gene and are responsible for producing proteins that are needed for many functions of the body.
INTRON RETENTION- The introns are retained in the final transcript in this event. Around 2- 5% of the genes that are reported to retain introns in humans. The gene splicing mechanisms retain the non- coding proteins of the gene which leads to a demornity in the protein structure and function.
ALTERNATIVE 3' AND 5' SPLICE SITE - These kinds of splicing include joining of different 5' and 3' splice sites. In this two or more kinds of alternative 5' splice sites compete for joining to two or more alternative 3' splice sites.

Note-
Most efficient methods for large scale detection of splice variants include computational prediction method and microarray analysis. A number of novel gene transcripts were detected using microarray based methods that were not detected using computational based methods. Another commonly used method for the discovery of novel genes is RT - PCR that is followed by splicing.