we have previously reported the presence of four dihydrofolate reductase messenger rnas differing in the length of 3 ' untranslated regions in murine cells ( setzer , d. r. , mcgrogan , m. , nunberg , j. h. , and schimke , r. t. ( 1980 ) cell 22 , 361-370 ) .
C0035696
messenger rnas
C0600680
untranslated regions