The following images attempt to illustrate
how pre-mRNA is altered to produce a processed mRNA ready for splicing.
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.
see the Flash movie for the following sequence of images,
The first step in mRNA
processing is the adding of a cap.
Capping occurs during transcription.
Certain signal sites
play key roles in helping to assemble complexes responsible
Polyadenylation involves several different
As these proteins go to work, the poly(A)
tail begins to grow.
The final product of mRNA processing is
a strand of mRNA that has been capped and had a poly(A) tail
added to it.