Rna Splicing And Processing Ppt To PdfBy Victor G. In and pdf 15.04.2021 at 03:33 4 min read
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In some genes the protein-coding sections of the DNA "exons" are interrupted by non-coding regions "introns". RNA splicing removes the introns from pre mRNA to produce the final set of instructions for the protein.
- RNA splicing
- Pre-mRNA splicing and human disease
- Mechanism of alternative splicing and its regulation (Review)
The discovery of the phenomenon that viral sequences are removed from a pre-mRNA and the remaining sequences are joined together led to a fundamental principle governing biology, known as RNA splicing. The identification stimulated theories for protein diversity, such as alternative splicing, which over time have been realized repeatedly through experiments. 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.
In the appropriate cell type and at the correct developmental stage, ribonucleic acid RNA polymerase transcribes an RNA copy of a gene, the primary transcript. However, the primary transcript may contain many more nucleotides than are needed to create the intended protein. In addition, the primary transcript is vulnerable to breakdown by RNA-degrading enzymes. Before the primary transcript can be used to guide protein synthesis, it must be processed into a mature transcript, called messenger RNA mRNA. This is especially true in eukaryotic cells. Processing events include protection of both ends of the transcript and removal of intervening nonprotein-coding regions.
Pre-mRNA splicing and human disease
The precision and complexity of intron removal during pre-mRNA splicing still amazes even 26 years after the discovery that the coding information of metazoan genes is interrupted by introns Berget et al. Adding to this amazement is the recent realization that most human genes express more than one mRNA by alternative splicing, a process by which functionally diverse protein isoforms can be expressed according to different regulatory programs. Given that the vast majority of human genes contain introns and that most pre-mRNAs undergo alternative splicing, it is not surprising that disruption of normal splicing patterns can cause or modify human disease. The purpose of this review is to highlight the different mechanisms by which disruption of pre-mRNA splicing play a role in human disease. Several excellent reviews provide detailed information on splicing and the regulation of splicing Burge et al.
During splicing, introns non-coding regions are removed and exons coding regions are joined together. For nuclear-encoded genes , splicing takes place within the nucleus either during or immediately after transcription. For those eukaryotic genes that contain introns, splicing is usually required in order to create an mRNA molecule that can be translated into protein. For many eukaryotic introns, splicing is carried out in a series of reactions which are catalyzed by the spliceosome , a complex of small nuclear ribonucleoproteins snRNPs. Self-splicing introns , or ribozymes capable of catalyzing their own excision from their parent RNA molecule, also exist. Several methods of RNA splicing occur in nature; the type of splicing depends on the structure of the spliced intron and the catalysts required for splicing to occur.
Mechanism of alternative splicing and its regulation (Review)
The splicing reactions have no net gain in the no. Yet, a large number of ATP is consumed, not for the chemistry, but to properly assemble and operate the slicing machinery. Same promoter and the tripartate leader sequence for all the transcripts which are resulted from alternative splicingBox Adenovirus and the discovery of splicing. The spliceosome machineryRNA splicing is carried out by a large complex called the spliceosomeSpliceosome comprises about proteins and 5 RNAs and is similar in size with ribosomes. Many functions of spliceosome are carried out by RNAs rather by proteins.
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Мгновение спустя, как в одном из самых страшных детских кошмаров, перед ней возникло чье-то лицо. Зеленоватое, оно было похоже на призрак. Это было лицо демона, черты которого деформировали черные тени.