RNase H-catalyzed site-specific deadenylylation of rabbit alpha- and beta- globin mRNAs. Secondary structure of 3'-noncoding regions.

A general method is described for the removal of 3'-terminal polyadenylate tracts from eukaryotic messenger RNA to generate essentially homogeneous length products that can be 3'-end labeled and sequenced. Hybridization of specific oligodeoxyribonucleotides was used to direct ribonuclease H to the junction of the 3'-noncoding region and the polyadenylate sequence of rabbit alpha and beta globin mRNAs. Site-specific deadenylylation of both globin mRNAs is demonstrated by partial enzymatic sequence analysis following 3'-terminal labeling with 5'-pCp (where p indicates the labeled phosphate group). The secondary structure of the 3'-noncoding region is studied by enzymatic digestion with S1 nuclease and cobra venom ribonuclease. Structural features of the 3'-noncoding regions of these mRNAs are described, including the protein synthesis termination and the poly(A) addition recognition sites.