Friday, September 16, 2005

Types of RNA

In response to a comment from a while back (with regards to What exactly is a gene?) ...

There are five main classes of RNA transcripts:

mRNA - this stands for messenger RNA, and these represent the products of the majority of genes ... however by some estimates make up as little as 10% of the RNA in a cell at any given time.

rRNA - for ribosomal RNA. This forms the structural component of the ribosome, the machine that translates mRNA into protein. Interestingly, all the catalytic sites in the ribosome are formed by the bases coming off RNA. Click here for more on catalytic RNA.

tRNA - for ... well these types of RNA form a "t" shape. Each of these RNAs can recognize 1-3 codons (the 3 nucleotide code present in DNA and RNA) on one end via it's anti-codon loop and is attached to an amino acid via it's other end. As the ribosome "translates" mRNA into protein, tRNAs enter the ribosome and match amino acids to the mRNA's successive codons.

snRNAs - for small nuclear RNAs. These are catalytic RNAs that perform mRNA splicing.

miRNA - for micro RNA. These small RNAs are used to destroy mRNAs with complementary sequences. This process is called RNAi (for RNA interference).

RNA has been hot of late. Science recently dedicated a whole issue to the RNA field. Now I just have to publish my work ... ok back to the bench!