Biology 2581B Lecture Notes - Lecture 18: Rna Editing, Cytochrome C Oxidase Subunit I, Selaginella
28 Apr 2016
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Lecture 18: more on modifications & some bioinformatics. Spikemoss (selaginella) as an example of rna editing (also called post-transcriptional editing). Selaginella often alters the c"s in transcripts to u"s. There can be 1000"s of c-to-u editing sites: the cox1 gene in selaginella has >200 c-to-u editing sites. After editing, there are quite a few changes to the amino acid sequence from edited rna. Note: this is the mitochondrial genome because cox1: to edit the c u transitions, proteins called editsomes are needed to bind to the rna cytosine and change it to a u. Therefore, you need tons of these editing proteins to create one protein from the edited transcript. This form of rna editing (c u by editsomes) is unique to vascular plant chloroplast and mitochondrial genomes. However, rna editing itself has arisen multiple times throughout evolution such as in bacteria and eukaryotic nuclear genomes. Trypanosomes as another example with their maxi-circle and mini-circle mitochondrial genomes.
