THE BIOCHEMISTRY OF POLYADENYLATION

During the synthesis of mRNA in the nucleus, 3'-ends are generated by endonucleolytic cleavage followed by polyadenylation. The machinery re sponsible for this simple reaction is surprisingly complex. In vitro r econstitution of 3'-end processing has demonstrated the importance of cooperative interactions in RNA recognition and catalysis. However, th e inventory of processing factors is still incomplete and important me chanistic questions have not yet been answered.