Search results
Results from the WOW.Com Content Network
Polyadenylation occurs during and/or immediately after transcription of DNA into RNA. After transcription has been terminated, the mRNA chain is cleaved through the action of an endonuclease complex associated with RNA polymerase. After the mRNA has been cleaved, around 250 adenosine residues are added to the free 3' end at the cleavage site.
The pre-mRNA processing at the 3' end of the RNA molecule involves cleavage of its 3' end and then the addition of about 250 adenine residues to form a poly(A) tail.The cleavage and adenylation reactions occur primarily if a polyadenylation signal sequence (5'- AAUAAA-3') is located near the 3' end of the pre-mRNA molecule, which is followed by another sequence, which is usually (5'-CA-3') and ...
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 (), processing, nuclear export (three alternative pathways), sequestration in P-bodies for storage or degradation and ...
These short tailed mRNAs are activated by cytoplasmic polyadenylation after fertilisation, during egg activation. [47] In animals, poly(A) ribonuclease can bind to the 5′ cap and remove nucleotides from the poly(A) tail. The level of access to the 5′ cap and poly(A) tail is important in controlling how soon the mRNA is degraded.
(See Central dogma of molecular biology). mRNA structure, approximately to scale for a human mRNA, where the median length of 3′UTR is 700 nucleotides. In molecular genetics, the three prime untranslated region (3′-UTR) is the section of messenger RNA (mRNA) that immediately follows the translation termination codon.
Termination of transcription occurs due to termination signal. In molecular biology , a termination signal is a sequence that signals the end of transcription or translation . [ 1 ] Termination signals are found at the end of the part of the chromosome being transcribed during transcription of mRNA .
Eukaryotic mRNA precursors must be processed in the nucleus (e.g., capping, polyadenylation, splicing) in ribosomes before they are exported to the cytoplasm for translation. Translation can also be affected by ribosomal pausing, which can trigger endonucleolytic attack of the tRNA, a process termed mRNA no-go decay. Ribosomal pausing also aids ...
Inside cells, there is a balance between the processes of translation and mRNA decay. [2] Messages which are being actively translated are bound by polysomes and the eukaryotic initiation factors eIF-4E and eIF-4G (in eukaryotes). This blocks access to the cap by the decapping enzyme DCP2 and protects the mRNA molecule. In nutrient-starvation ...