How do exon junction complexes function?
How do exon junction complexes function?
The Exon Junction Complex (EJC) plays a central role in post-transcriptional gene expression control. EJCs tag mRNA exon junctions following intron removal by spliceosomes and accompany spliced mRNAs from the nucleus to the cytoplasm where they are displaced by the translating ribosomes1,2.
What is the exon definition model?
The exon definition model involves an additional layer of regulation: before catalytic cross-intron complexes can form, transitory cross-exon U1-U2 snRNP complexes are required to stabilize initial U1/U2 snRNP binding to splice sites (Fig. 3 A, right).
What is exon function?
Exon Function Exons are pieces of coding DNA that encode proteins. Different exons code for different domains of a protein. The domains may be encoded by a single exon or multiple exons spliced together. Exons also allow for multiple proteins to be translated from the same gene through alternative splicing.
How does exon splicing work?
The stretches of DNA that do code for amino acids in the protein are called exons. During the process of splicing, introns are removed from the pre-mRNA by the spliceosome and exons are spliced back together. If the introns are not removed, the RNA would be translated into a nonfunctional protein.
What is a exon exon junction?
An exon junction complex (EJC) is a protein complex which forms on a pre-messenger RNA strand at the junction of two exons which have been joined together during RNA splicing. The EJC consists of a stable heterotetramer core, which serves as a binding platform for other factors necessary for the mRNA pathway.
Which protein is found in the exon junction complex?
When assembled in vitro, this so-called ‘exon–exon junction complex’ (EJC) contains at least five proteins: SRm160, DEK, RNPS1, Y14 and REF. To better investigate its functional attributes, we now describe a method for generating spliced mRNAs both in vitro and in vivo that either do or do not carry the EJC.
What is an exon and intron?
An intron is a portion of a gene that does not code for amino acids. The parts of the gene sequence that are expressed in the protein are called exons, because they are expressed, while the parts of the gene sequence that are not expressed in the protein are called introns, because they come in between the exons.
What is intron and exon definition?
Editor) Introns and exons are nucleotide sequences within a gene. Introns are removed by RNA splicing as RNA matures, meaning that they are not expressed in the final messenger RNA (mRNA) product, while exons go on to be covalently bonded to one another in order to create mature mRNA.
What is the difference between intron and exon?
Introns and exons are nucleotide sequences within a gene. Introns are removed by RNA splicing as RNA matures, meaning that they are not expressed in the final messenger RNA (mRNA) product, while exons go on to be covalently bonded to one another in order to create mature mRNA.
What is Exon Intron?
Exons are termed as nucleic acid coding sequences, which are present in mRNA. Introns are the non-coding sequences present in the DNA, which are removed by RNA splicing before translation.
What do exons and introns do?
Introns are noncoding sections of an RNA transcript, or the DNA encoding it, that are spliced out before the RNA molecule is translated into a protein. The sections of DNA (or RNA) that code for proteins are called exons. Splicing produces a mature messenger RNA molecule that is then translated into a protein.
What is the function of the exon junction complex?
There it plays a major role in post-transcriptional regulation of mRNA. It is believed that exon junction complexes provide a position-specific memory of the splicing event. The EJC consists of a stable heterotetramer core, which serves as a binding platform for other factors necessary for the mRNA pathway.
How does EJC interact with other proteins?
In order for the binding of the complex to the mRNA to occur, the eIF4AIII factor is inhibited, stopping the hydrolysis of ATP. This recognizes EJC as an ATP dependent complex. EJC also interacts with a large number of additional proteins; most notably SR proteins. These interactions are suggested to be important for mRNA compaction.
What is the role of EJC in mRNA compaction?
EJC also interacts with a large number of additional proteins; most notably SR proteins. These interactions are suggested to be important for mRNA compaction. The role of EJC in mRNA export is controversial. The EJC is made up of several key protein components: RNPS1, Y14, SRm160, Aly/REF and Magoh, among others.
