What enzyme is involved in splicing?
The RNA-splicing endonuclease is an evolutionarily conserved enzyme responsible for the excision of introns from nuclear transfer RNA (tRNA) and all archaeal RNAs.
What enzyme repairs breaks in DNA?
Double-strand breaks are repaired through one of two mechanisms: nonhomologous end joining (NHEJ) or homologous recombination repair (HRR). In NHEJ, an enzyme called DNA ligase IV uses overhanging pieces of DNA adjacent to the break to join and fill in the ends.
What is a splicing activator?
Splicing activators may modulate spliceosome assembly through the formation of multiple PPIs, and in this way ensure bona-fide splice site recognition and exon inclusion.
What are the 4 types of DNA repair?
At least five major DNA repair pathways—base excision repair (BER), nucleotide excision repair (NER), mismatch repair (MMR), homologous recombination (HR) and non-homologous end joining (NHEJ)—are active throughout different stages of the cell cycle, allowing the cells to repair the DNA damage.
Does splicing occur during transcription?
Splicing and transcription have been generally been studied in isolation, although in vivo pre-mRNA splicing occurs in concert with transcription. The two processes appear to be functionally connected because a number of variables that regulate transcription have been identified as also influencing splicing.
What is splicing mechanism?
Gene splicing is a post-transcriptional modification in which a single gene can code for multiple proteins. Gene Splicing is done in eukaryotes, prior to mRNA translation, by the differential inclusion or exclusion of regions of pre-mRNA. Gene splicing is an important source of protein diversity.
How do you repair damaged DNA?
Once DNA damage is recognized in the nuclear genome, bulky adducts, small miscoding lesions, single-strand breaks, or non-complex double-strand breaks (DSBs) can be directly repaired by nucleotide excision repair (NER), base excision repair (BER), and non-homologous end-joining (NHEJ), respectively.
How is deamination of cytosine repaired?
Spontaneous deamination converts cytosine to uracil, which is excised from DNA by the enzyme uracil-DNA glycosylase, leading to error-free repair.
What regulates alternative splicing?
Splicing is regulated by trans-acting proteins (repressors and activators) and corresponding cis-acting regulatory sites (silencers and enhancers) on the pre-mRNA. However, as part of the complexity of alternative splicing, it is noted that the effects of a splicing factor are frequently position-dependent.
What does alternative splicing produce?
Alternative splicing is a molecular mechanism that modifies pre-mRNA constructs prior to translation. This process can produce a diversity of mRNAs from a single gene by arranging coding sequences (exons) from recently spliced RNA transcripts into different combinations.
What are the two types of DNA repair?
There are two main mechanisms for repairing double strand breaks: homologous recombination and classical nonhomologous end joining. Homologous recombination involves the exchange of nucleotide sequences to repair damaged bases on both strands of DNA through the utilization of a sister chromatid.
What are the three steps in DNA repair?
There are three types of repair mechanisms: direct reversal of the damage, excision repair, and postreplication repair.
How do spliceosomal inhibitors affect DNA repair?
Although evidence that splicing regulates DNA repair is accumulating, the underlying mechanism (s) remain unclear. Here, we report that short-term inhibition of pre-mRNA splicing by spliceosomal inhibitors impairs cellular repair of DNA double-strand breaks.
How does DNA splicing increase the coding capacity of a gene?
During a typical DNA splicing event, the pre-mRNA transcribed from one gene can lead to diffrent mature mRNA molecules that generate multiple funtional proteins. Thus, DNA splicing enables a single gene to increase is coding capacity, allowing the synthesis of protein isoforms that are structurally and functionally distinct.
Why is DNA splicing important for genetic diversity?
DNA splicing is an important source of protien diversity. During a typical DNA splicing event, the pre-mRNA transcribed from one gene can lead to diffrent mature mRNA molecules that generate multiple funtional proteins. Thus, DNA splicing enables a single gene to increase is coding capacity, allowing the synthesis of protein isoforms
What is the mechanism of DNA repair?
Mechanisms. Damage to DNA alters the spatial configuration of the helix, and such alterations can be detected by the cell. Once damage is localized, specific DNA repair molecules bind at or near the site of damage, inducing other molecules to bind and form a complex that enables the actual repair to take place.