Mature messenger RNA, often abbreviated as mature mRNA is a eukaryotic RNA transcript that has been spliced and processed and is ready for translation in the course of protein synthesis. Unlike the eukaryotic RNA immediately after transcription known as precursor messenger RNA, mature mRNA consists exclusively of exons and has all introns removed. Difference between Prokaryotic and Eukaryotic mRNA: 1. The mRNA of many types of bacteria and bacteriophage are polygenic, that is a single mRNA is transcribed by the several structural genes of an operon. It also contains many sites for initiation and termination codons. That is a single mRNA can code for several different protein molecules.
Eukaryotic mRNAs last for several hours, whereas the typical E. coli mRNA lasts no more than five seconds. Pre-mRNAs are first coated in RNA-stabilizing proteins; these protect the pre-mRNA from degradation while it is processed and exported out of the nucleus. Eukaryotic mRNA is sometimes edited or spliced before it leaves the nucleus, so they need to regulate which mRNAs can leave the nucleus. Moreover, translation of the instructions encoded in the mRNA is a much more highly regulated process in eukaryotes, and these modifications also play important roles in .
RNA synthesis. Whereas a single RNA polymerase species synthesizes all RNAs in prokaryotes, there are three different RNA polymerases in eukaryotic systems. 1. RNA polymerase I synthesizes rRNA.. 2. RNA polymerase II synthesizes mRNA. In eukaryotes, the mRNA molecules always code for one protein, whereas in prokaryotes, many mRNAs code for several proteins.Bookshelf ID: NBK21853. Mature mRNAs contain a stretch of adenosines at the 3′-end of the transcript referred to as the poly(A) tail. 3′-end processing is the addition of the poly(A) tail and involves two steps: endonucleolytic cleavage followed by polyadenylation. Cleavage of the pre-mRNA requires recognition of an AAUAAA sequence near the 3′-end.