polyadenylate polymerase การใช้

• When the RNA is cleaved, polyadenylation starts, catalysed by polyadenylate polymerase.
• Some lineages, like archaea and cyanobacteria, never evolved a polyadenylate polymerase.
• This reaction is catalyzed by polyadenylate polymerase.
• Polyadenylate polymerase builds the poly ( A ) tail by adding adenosine monophosphate units from adenosine triphosphate to the RNA, cleaving off pyrophosphate.
• Depending on the cell type, the polymerase can be the same type of polyadenylate polymerase ( PAP ) that is used in the nuclear process, or the cytoplasmic polymerase GLD-2.
• Another protein, PAB2, binds to the new, short poly ( A ) tail and increases the affinity of polyadenylate polymerase for the RNA . When the poly ( A ) tail is approximately 250 nucleotides long the enzyme can no longer bind to CPSF and polyadenylation stops, thus determining the length of the poly ( A ) tail.
• The protein is the final addition to a large protein complex that also contains smaller assemblies known as the cleavage and polyadenylation specificity factor ( CPSF ) and cleavage stimulatory factor ( CtSF ) and its binding is a necessary prerequisite to the cleavage of the 3'end of the pre-mRNA . After cleavage of the 3'signaling region that directs the assembly of the complex, polyadenylate polymerase ( PAP ) adds the polyadenine tail to the new 3'end.