Mature mRNA: Definition, Features, and Functions

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Mature mRNA Definition

mRNA also known as the messenger RNA is a type of RNA, whose function is protein synthesis. Messenger RNA is synthesized from DNA by the process transcription. For the mRNA to function it needs to be processed and be active so that the code can be read by the ribosomes in eukaryotes.

In the nucleus, synthesis takes place. RNA exist in two forms precursor mRNA and mature RNA. precursor mRNA is formed after transfer the genetic information in the DNA, which is transcription and then is transported to cytoplasm, where ribosomes are present and will carry out translation along with ribosomes to form mature RNA. This all takes place in the nucleus.

Mature mRNA Structure
Image credit: Wikipedia

Mature mRNA Characteristics

Mature mRNA is a type of ribonucleic acid which is single stranded and possess genes which gets translated to proteins. The pre- mRNA undergoes transcription and translation to form mature-RNA. Both the forms of RNA differ in intron and exon, which is absent in m-RNA and possess a cap at 5’ end and a poly A tail at the 3’ end.

Biological Function of Mature mRNA

The genetic information for the protein is possessed by mRNA, when it interacted with ribosome and tRNA. After the post- transcriptional changes, pre-mRNA has obtained it and after processing and maturing it will move from nucleus and cytosol, and ribosomes along with tRNA will translate the message to synthesize protein.

Mature mRNA Biological Reactions

RNA exist in two forms precursor mRNA and mature RNA. precursor mRNA is formed after transfer the genetic information in the DNA, which is transcription and then is transported to cytoplasm, where ribosomes are present and will carry out translation along with ribosomes to form mature RNA.

This all takes place in the nucleus. For the m-RNA to function it needs to be processed and be active so that the code can be read by the ribosomes in eukaryotes. The double stranded DNA uncoils by fragmenting the hydrogen bond, thus the two strands are separated and will act as the template strand or the antisense strand for MRNA synthesis.

Transcription occurs in 5’-3’ direction and RNA polymerase will move in 3’-5’ direction. Primer is not required and adenine uracil base pairs can be utilized in transcription.

There are various types of RNA polymerase but the one involved is RNA polymerase 2 for pre-mRNA synthesis, however only type is seen in prokaryotes and the process takes place in cytoplasm and for eukaryotes in nucleus and then again moved to cytoplasm.

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Steps of mRNA Synthesis

1. To the template DNA strand, is a promoter region where the transcription factors and RNA polymerase binds.

2. Thus, the replication fork is formed and the strands uncoil, due to hydrogen bond getting broken down and to the bases, sigma factor attaches.

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3. Polymerase will add nucleotides opposite to the template strand and only a single strand will take part in transcription where the polymerase reads from 3’-5’ direction and the newly synthesized strand will be formed from 5’-3’ and the nucleotides added will be are adenosine, uridine, cytidine and guanosine monophosphate which will be added on the 3’end hydroxyl group. Thus, MRNA strand will be formed this way.

4. M-RNA transcript will be made by ribose sugar and the phosphate backbone. 5. The newly synthesized pre-M-RNA is released due to breakage between DNA and RNA. 6. The pre-M-RNA undergoes splicing, caping, poly A tail addition to turn into mature M-RNA that will move through the pores of cytoplasm.

mRNA Synthesis Regulators

Transcription factors are the regulators, which binds to DNA, but are protein and called the enhancers. These transcription factors can initiate as well as inhibit the process by putting the enzyme on charge will permit or inhibit the entry of RNA polymerase to DNA. Genes can be suppressed by silencers, which can be situated upstream or downstream. Transcription can be inhibited by transcription factors which will disassemble the initiation complex, which will trigger RNA polymerase.

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