The answer lies in the spliceosome, a cellular machine that, at first glance, seems to do some pretty straightforward pruning of messenger RNA (mRNA). As the cell transcribes your DNA’s nucleic acid sequence into RNA, the spliceosome lands on the newly forming mRNA strand, where it chops out unnecessary pieces, called introns, and joins together the leftover, essential sequences, called exons. The edited mRNA is then exported to the cell’s cytoplasm, where it gets translated into protein. Most strands of unspliced mRNA, otherwise known as pre-mRNA, have about a dozen introns that can be removed. Yet the spliceosome doesn’t always link together the remaining exons in a straightforward manner.
by Sarah Everts |
October 05, 2015