Some transcripts can undergo alternative splicing
. This regulated process makes different mRNAs and proteins from the same initial RNA transcript. Some mRNAs are targeted by small regulatory RNAs, including miRNAs, which can cause mRNA degradation or block translation.
Is alternative splicing post-transcriptional regulation?
After being produced, the stability and distribution of the different transcripts is regulated (post-transcriptional regulation) by means of RNA binding protein (RBP) that control the various steps and rates controlling events such as alternative splicing, nuclear degradation (exosome), processing, nuclear export ( …
Is alternative RNA splicing post-transcriptional?
Therefore, alternative splicing, a type of post-transcriptional modification, is the process by which exons or portions of exons or non-coding regions within a pre-mRNA transcript are
differentially joined or skipped
, resulting in multiple protein isoforms being encoded by a single gene.
Is splicing post translational modification?
The revelation that many splicing factors are
post-translationally modified
strongly suggests that many of the dynamic rearrangements that occur during the splicing cycle are regulated, in part, by the addition and removal of these PTMs.
What kind of regulation is alternative splicing?
Alternative splicing (AS) is
a mechanism of regulation of the proteome via enabling the production of multiple mRNAs from a single gene
. To date, the dynamics of AS and its effects on the protein sequences of individuals in a large and genetically unrelated population of trees have not been investigated.
What are the three steps of post-transcriptional modification?
This process includes three major steps that significantly modify the chemical structure of the RNA molecule:
the addition of a 5′ cap, the addition of a 3′ polyadenylated tail, and RNA splicing.
What are some examples of post-translational regulation?
Such post-translational modifications are generally reversible, one enzyme adds the modifying group and another can remove it. For example,
proteins are phosphorylated by enzymes known as protein kinases
, while protein phosphotases remove such phosphate groups.
What is the difference between post transcriptional and post-translational modification?
Post-transcriptional mechanisms based on alternative splicing and RNA processing, as well as RNA silencing define the actual transcriptome supporting the cold stress response. Post-translational modifications such as ubiquitination and sumoylation
regulate the activity of preexisting molecules
.
Why does post-translational modification occur?
PTMs are chemical modifications that play a key role in functional proteomic because they regulate activity, localization, and interaction with other cellular molecules such as proteins, nucleic acids, lipids and cofactors. Post-translational modifications are
key mechanisms to increase proteomic diversity
.
Is DNA methylation a post-translational modification?
Proteomic analysis of posttranslational modifications. … A plethora of PTMs have currently been described, including phosphorylation, acetylation, glycosylation, methylation, ubiquitylation, sumoylation, myristoylation, and S-nitrosylation.
What triggers alternative splicing?
Alternative splicing is the process of selecting different combinations of splice sites within a messenger RNA precursor (pre-mRNA) to
produce variably spliced mRNAs
. These multiple mRNAs can encode proteins that vary in their sequence and activity, and yet arise from a single gene.
What is the difference between constitutive splicing and alternative splicing?
Constitutive splicing is the process of intron removal and exon ligation of the majority of the exons in the order in which they appear in a gene. Alternative splicing is
a deviation from this preferred sequence where certain exons are skipped resulting in various forms of mature mRNA
.
What is the purpose of alternative splicing?
The overall function of alternative splicing is
to increase the diversity of the mRNA expressed from the genome
. Due to the combinatorial control mechanisms that regulate alternative exon recognition, splicing programs coordinate the generation of mRNA isoforms from multiple genes.
Do bacteria have post transcriptional modification?
There are
post-translational modifications
in prokaryotes, but they are less common and mostly of a different nature. Bacteria do not have systems for N-linked or O-linked glycosylation and don’t have widespread serine and tyrosine phosphorylation, for example.
Does splicing occur before polyadenylation?
For short transcription units, RNA splicing usually follows cleavage and polyadenylation of the 3′ end of the primary transcript. But for long transcription units containing multiple exons, splicing of exons in the nascent RNA usually
begins before transcription of the gene is complete
.
How is 5cap added?
The capping process replaces the triphosphate group with another structure called the “cap”. The cap is added by
the enzyme guanyl transferase
. This enzyme catalyzes the reaction between the 5′ end of the RNA transcript and a guanine triphosphate (GTP) molecule.
