Joseph D. Puglisi is in the Department of Structural
Biology, Stanford University School of Medicine, Stanford,
California 94305-5126, USA.
puglisi@stanford.edu
The U1A protein regulates the activity of poly(A) polymerase by
interacting with an RNA element in the 3' untranslated region of its
mRNA. The structure of the trimolecular complex made up of two U1A molecules
bound to the target RNA explains the cooperative regulation in this system.
