Contribution of polyadenylate sequences to the translational efficiency of globin messenger RNAs.
mRNAs from reticulocyte polysomes were fractionated by chromatography on poly(U)-Sepharose and thermal elution. The molar ratio of alpha- to beta-globin mRNA was found to be 2:1 and 1:1 respectively in short- and long-poly(A) size classes. Translational analyses indicated that the globin mRNAs containing long poly(A) tracts (with a mean length of about 70 nucleotides) directed protein synthesis with higher rates than did mRNA containing short poly(A) tracts (15-35 nucleotides). Experiments performed with sub-saturating mRNA concentrations showed that the digestion with RNAase H induced a decrease in the translational capacity of both globin mRNAs and an increase in the alpha- to beta-globin synthesis ratio. No correlation was observed between the size of the poly(A) tail in mRNA and the optimal K+ requirement for translation.
Departament de Microbiologia, Facultat de Farmacia, Universitat de València, Spain.
A
A
Parets Soler
D
D
Gozalbo
J
J
Zueco
R
R
Sentandreu
D001483:Base Sequence; D002846:Chromatography, Affinity; D004247:DNA / Q000235:genetics; D004591:Electrophoresis, Polyacrylamide Gel; D005914:Globins / Q000096:biosynthesis / Q000235:genetics*; D008969:Molecular Sequence Data; D011061:Poly A / Q000032:analysis*; D011188:Potassium / Q000494:pharmacology; D014176:Protein Biosynthesis / Q000187:drug effects; D012333:RNA, Messenger / Q000235:genetics*
D012333:RNA, Messenger; D011061:Poly A; D005914:Globins; D004247:DNA; D011188:Potassium