Types of RNA
Coding RNA
- Messenger RNA (mRNA) – carries the genetic code from DNA is a form that can be sued
in protein synthesis. This sequence determines the order of amino acids in a protein
- Once transcribed from DNA, eukaryotic RNA briefly exists as precursor m-RNA (pre-
mRNA)
- RNA splicing processes this pre-mRNA into mature mRNA by removing non-coding RNA
called introns
Non-coding RNA
- Ribosomal RNA (rRNA) – catalytic component of ribosomes. In the cytoplasm, the rRNAs
and protein components combine to form the ribosome, which binds mRNA and
synthesizes proteins (protein translation)
- Transfer RNA (tRNA) – this is a small RNA chain consisting of around 80 nucleotides.
During translation, tRNAs transfer specific amino acids that correspond to the mRNA
sequence in the polypeptide chain at the ribosome
- Small nuclear RNA (snRNA) – these are associated with a group of specific proteins to
form the nucleoprotein complexes known as small nuclear ribonucleoproteins (snRNP)
in the nucleus. They are mainly involved with splicing pre-mRNA
- Small nucleolar RNA (snoRNA) – these are components of small nucleolar
ribonucleoproteins which are responsible for sequence-specific nucleotide modification
- Piwi-interacting RNA (piRNA) – these bind the PIWI subfamily proteins which are
involved in maintaining genome stability in germline cells. piRNA also plays a role in
gametogenesis
- MicroRNA (miRNA) – these are small ncRNAs of about 22 nucleotides which mediate
post-transcriptional gene silencing through RNA interference (RNAi), whereby an effector
complex of miRNA and enzymes targets complementary mRNA by either blocking it from
being translated or accelerating degradation
- Long noncoding RNA (lncRNA) - these are a heterogenous group of non-coding
transcripts which make up the largest proportion of the mammalian non-coding
transcriptome. These are essential in many physiological processes
Coding RNA
- Messenger RNA (mRNA) – carries the genetic code from DNA is a form that can be sued
in protein synthesis. This sequence determines the order of amino acids in a protein
- Once transcribed from DNA, eukaryotic RNA briefly exists as precursor m-RNA (pre-
mRNA)
- RNA splicing processes this pre-mRNA into mature mRNA by removing non-coding RNA
called introns
Non-coding RNA
- Ribosomal RNA (rRNA) – catalytic component of ribosomes. In the cytoplasm, the rRNAs
and protein components combine to form the ribosome, which binds mRNA and
synthesizes proteins (protein translation)
- Transfer RNA (tRNA) – this is a small RNA chain consisting of around 80 nucleotides.
During translation, tRNAs transfer specific amino acids that correspond to the mRNA
sequence in the polypeptide chain at the ribosome
- Small nuclear RNA (snRNA) – these are associated with a group of specific proteins to
form the nucleoprotein complexes known as small nuclear ribonucleoproteins (snRNP)
in the nucleus. They are mainly involved with splicing pre-mRNA
- Small nucleolar RNA (snoRNA) – these are components of small nucleolar
ribonucleoproteins which are responsible for sequence-specific nucleotide modification
- Piwi-interacting RNA (piRNA) – these bind the PIWI subfamily proteins which are
involved in maintaining genome stability in germline cells. piRNA also plays a role in
gametogenesis
- MicroRNA (miRNA) – these are small ncRNAs of about 22 nucleotides which mediate
post-transcriptional gene silencing through RNA interference (RNAi), whereby an effector
complex of miRNA and enzymes targets complementary mRNA by either blocking it from
being translated or accelerating degradation
- Long noncoding RNA (lncRNA) - these are a heterogenous group of non-coding
transcripts which make up the largest proportion of the mammalian non-coding
transcriptome. These are essential in many physiological processes
