mRNA Splicing: First Look

The following images illustrate the basic steps involved in splicing mRNA in preparation for translation. Our goal is to emphasize the key steps in this process. Clicking on each of the thumbnail images will bring up a larger, labeled version of the described scene.

To see the Windows Media movie for the following sequence of images, click here.

	When mRNA is ready for splicing it is known as a primary transcript. Primary transcripts contains exons and introns.
	The spliceosome mediates mRNA splicing.
	The intron is first cleaved at its 5' end.
	Cleavage then occurs at the 3' end of the intron.
	Following the removal of the intron, the two exons are combined to form a mature strand of mRNA. The mRNA is then ready to undergo translation.