Table of Contents
What does cytoplasmic polyadenylation regulate?
Cytoplasmic polyadenylation is the process by which dormant, translationally inactive mRNAs become activated via the elongation of their poly(A) tails in the cytoplasm. This process is regulated by the conserved cytoplasmic polyadenylation element binding (CPEB) protein family.
Where does polyadenylation occur in the cytoplasm?
Cytoplasmic polyadenylation should be distinguished from nuclear polyadenlyation; cytoplasmic polyadenylation occurs in the cytoplasm in specific mRNAs as opposed to occurring in the nucleus and affecting almost all eukaryotic mRNAs.
Do all Mrna have poly A tail?
Poly(A)-binding protein also can bind to, and thus recruit, several proteins that affect translation, one of these is initiation factor-4G, which in turn recruits the 40S ribosomal subunit. However, a poly(A) tail is not required for the translation of all mRNAs.
Why is polyadenylation of mRNA done?
The polyA tail is a long chain of adenine nucleotides that is added to a mRNA molecule during RNA processing. The polyA tail makes the RNA molecule more stable and prevents its degradation and allows the mature mRNA molecule to be exported from the nucleus and translated into a protein by ribosomes in the cytoplasm.
What does the poly-A tail do on mRNA?
The poly-A tail makes the RNA molecule more stable and prevents its degradation. Additionally, the poly-A tail allows the mature messenger RNA molecule to be exported from the nucleus and translated into a protein by ribosomes in the cytoplasm.
What is polyadenylation used for?
In eukaryotes, polyadenylation is part of the process that produces mature mRNA for translation. In many bacteria, the poly(A) tail promotes degradation of the mRNA. It, therefore, forms part of the larger process of gene expression.
What is the function of polyadenylation?
Then an enzyme called poly-A polymerase adds a chain of adenine nucleotides to the RNA. This process, called polyadenylation, adds a poly-A tail that is between 100 and 250 residues long. The poly-A tail makes the RNA molecule more stable and prevents its degradation.
What is polyadenylation process?
Polyadenylation is the addition of a poly(A) tail to an RNA transcript, typically a messenger RNA (mRNA). The poly(A) tail consists of multiple adenosine monophosphates; in other words, it is a stretch of RNA that has only adenine bases.
What is the polyadenylation signal sequence?
In the mammalian system, effective polyadenylation requires two main sequence components: a highly conserved AAUAAA signal located 10–30 nucleotide 5′ to the cleavage site and a more variable GU-rich element, 20–40 bases 3′ of the site (see Proudfoot 1991; Colgan and Manley 1997 for reviews).
How does polyA polymerase work?
Poly(A) Polymerase binds specifically to ATP and adds it at the end of a messenger RNA chain. This structure contains an oligo(A) polynucleotide with five nucleotides, an ATP molecule, and a magnesium ion. The enzyme is an inactive mutant with the catalytic aspartate 154 changed to alanine.
What is the function of polyadenylation signal?
Polyadenylation (polyA) signal sequences from various genes are added to mammalian vectors to ensure proper mRNA processing and stability.
What does the polyadenylation signal do?
What is cytoplasmic polyadenylation element?
The cytoplasmic polyadenylation element (CPE) is a nucleotide sequence within the 3′ UTR of mRNAs which binds to the CPE-binding protein (CPEB). A highly conserved isoform of CPEB has been demonstrated to contain a prion-like domain in the N-terminus.
What does CPE stand for in biology?
The cytoplasmic polyadenylation element (CPE) is a sequence element found in the 3′ untranslated region of messenger RNA. While several sequence elements are known to regulate cytoplasmic polyadenylation, CPE is the best characterized. The most common CPE sequence is UUUUAU, though there are other variations.
Are polyadenylation response elements directly CPE-and CPEB-independent?
We demonstrate that polyadenylation response elements, originally identified in the 3′-UTR of the mRNA encoding the Mos proto-oncogene, direct CPE- and CPEB-independent poly-adenylation of an early class of Xenopus maternal mRNAs.
What is the function of CPEB protein?
CPEB, or cytoplasmic polyadenylation element binding protein, is a highly conserved RNA-binding protein that promotes the elongation of the polyadenine tail of messenger RNA. CPEB most commonly activates the target RNA for translation, but can also act as a repressor, dependent on its phosphorylation state.