MRNA: Difference between revisions
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Pre mRNA is the exact copy of the DNA sequence, containing [[Intron|introns]] and [[Exon|exons]]. This is not helpful in cloning experiments as bacteria and other [[Prokaryotes|prokaryotes]] do not have the capibility to process this form of mRNA and remove the introns. | Pre mRNA is the exact copy of the DNA sequence, containing [[Intron|introns]] and [[Exon|exons]]. This is not helpful in cloning experiments as bacteria and other [[Prokaryotes|prokaryotes]] do not have the capibility to process this form of mRNA and remove the introns. | ||
Mature mRNA is the product when pre mRNA undergoes ''processing''. This involves a process called 'splicing' which removes the non-coding introns. Processing also encompasses joining the coding exons together, an addition of a CAP at the 5' end and adding a [[Poly A tail|poly A tail to]] the[[3' end| 3' end]], to form a new strand with an uninterrupted sequence, which is then translated into [[ | Mature mRNA is the product when pre mRNA undergoes ''processing''. This involves a process called 'splicing' which removes the non-coding introns. Processing also encompasses joining the coding exons together, an addition of a CAP at the 5' end and adding a [[Poly A tail|poly A tail to]] the[[3' end| 3' end]], to form a new strand with an uninterrupted sequence, which is then translated into [[Amino acids|amino acids]] and [[Protien|proteins]]. Mature mRNA is required for protein cloning in the lab as it does not require any further processing by the [[Prokaryotes|prokaryotes]]. | ||
In the cell, mRNA has a half-life which dictates how long until it degrades naturally, or by enzymatic interactions. The stability of the mRNA can be effected by a number of factors including: length of the poly-A tail, or other proteins bound to it which prevent the action of degrading enzymes. | In the cell, mRNA has a half-life which dictates how long until it degrades naturally, or by enzymatic interactions. The stability of the mRNA can be effected by a number of factors including: length of the poly-A tail, or other proteins bound to it which prevent the action of degrading enzymes. | ||
mRNA can also be used to make [[CDNA|cDNA]] (copy DNA). An enzyme called [[Reverse transcriptase|Reverse transcriptase]] is used to convert mRNA into [[CDNA|cDNA]]. mRNA uses the nucleotide [[Uracil|uracil]], instead of [[Thymine|thymine]], which is found in [[DNA|DNA]]. | mRNA can also be used to make [[CDNA|cDNA]] (copy DNA). An enzyme called [[Reverse transcriptase|Reverse transcriptase]] is used to convert mRNA into [[CDNA|cDNA]]. mRNA uses the nucleotide [[Uracil|uracil]], instead of [[Thymine|thymine]], which is found in [[DNA|DNA]]. | ||
mRNA can be degraded via by a main endonucleases. Exosomes are the principle 3'-5' exonuclease and comprises of 3 main subunits; RRP6 subunit is only found in the nucleus and is 'preferentially associated with structured targets | mRNA can be degraded via by a main endonucleases. Exosomes are the principle 3'-5' exonuclease and comprises of 3 main subunits; RRP6 subunit is only found in the nucleus and is 'preferentially associated with structured targets<ref>Claudia Schneider, Grzegorz Kudla, Wiebke Wlotzka, Alex Tuck,David Tollervey1; Mol Cell. 2012 Nov 9; 48(3-3): 422–433</ref>. The RRP44 subunit also works from the 3'-5' end. Finally the core subunit is involved in RNA binding and acts as a helicase by unwinding the RNA. | ||
=== References === | |||
<references /> | |||
Revision as of 14:00, 24 October 2015
Messenger RNA (mRNA) is an important form of RNA, both in the body and in the lab. Physiologically, it is used as the coding template for proteins, i.e. it directly transcribes the sequence of nucleotides from the DNA template (in a process known as transcription), forming a second complementary strand which is later processed by rRNA and tRNA to form a new DNA strand.
There are two forms of mRNA that can be found in eukaryotic cells: pre-mRNA and mature mRNA.
Pre mRNA is the exact copy of the DNA sequence, containing introns and exons. This is not helpful in cloning experiments as bacteria and other prokaryotes do not have the capibility to process this form of mRNA and remove the introns.
Mature mRNA is the product when pre mRNA undergoes processing. This involves a process called 'splicing' which removes the non-coding introns. Processing also encompasses joining the coding exons together, an addition of a CAP at the 5' end and adding a poly A tail to the 3' end, to form a new strand with an uninterrupted sequence, which is then translated into amino acids and proteins. Mature mRNA is required for protein cloning in the lab as it does not require any further processing by the prokaryotes.
In the cell, mRNA has a half-life which dictates how long until it degrades naturally, or by enzymatic interactions. The stability of the mRNA can be effected by a number of factors including: length of the poly-A tail, or other proteins bound to it which prevent the action of degrading enzymes.
mRNA can also be used to make cDNA (copy DNA). An enzyme called Reverse transcriptase is used to convert mRNA into cDNA. mRNA uses the nucleotide uracil, instead of thymine, which is found in DNA.
mRNA can be degraded via by a main endonucleases. Exosomes are the principle 3'-5' exonuclease and comprises of 3 main subunits; RRP6 subunit is only found in the nucleus and is 'preferentially associated with structured targets[1]. The RRP44 subunit also works from the 3'-5' end. Finally the core subunit is involved in RNA binding and acts as a helicase by unwinding the RNA.
References
- ↑ Claudia Schneider, Grzegorz Kudla, Wiebke Wlotzka, Alex Tuck,David Tollervey1; Mol Cell. 2012 Nov 9; 48(3-3): 422–433