Binding of proteins to the PolyA signal sequence and to the

Binding of proteins to the PolyA signal sequence and to the U-rich region downstream, results in formation of a complex that brings these two regions into proximity. Cleavage of the pre-mRNA then takes place... downstream of the U-rich region between the polyA sequence and the U-rich region within the polyA signal sequence within the U-rich region

Solution

The cleavage of pre -mRNA takes place between the polyadenylation sequence and the GU-rich sequence (or U-rich sequence) at the cleavage site marked by the (5\'-CA-3\') sequences.

So answer is between poly A sequence and U+rich region