Translational regulation of human beta interferon mRNA: association of the 3' AU-rich sequence with the poly(A) tail reduces translation efficiency in vitro.
The 3' AU-rich region of human beta-1 interferon (hu-IFN beta) mRNA was found to act as a translational inhibitory element. The translational regulation of this 3' AU-rich sequence and the effect of its association with the poly(A) tail were studied in cell-free rabbit reticulocyte lysate. A poly(A)-rich hu-IFN beta mRNA (110 A residues) served as an inefficient template for protein synthesis. However, translational efficiency was considerably improved when the poly(A) tract was shortened (11 A residues) or when the 3' AU-rich sequence was deleted, indicating that interaction between these two regions was responsible for the reduced translation of the poly(A)-rich hu-IFN beta mRNA. Differences in translational efficiency of the various hu-IFN beta mRNAs correlated well with their polysomal distribution. The poly(A)-rich hu-IFN beta mRNA failed to form large polysomes, while its counterpart bearing a short poly(A) tail was recruited more efficiently into large polysomes. The AU-rich sequence-binding activity was reduced when the RNA probe contained both the 3' AU-rich sequence and long poly(A) tail, supporting a physical association between these two regions. Further evidence for this interaction was achieved by RNase H protection assay. We suggest that the 3' AU-rich sequence may regulate the translation of hu-IFN beta mRNA by interacting with the poly(A) tail.
Grafi
G
G
Department of Plant Genetics, Weizmann Institute of Science, Hebrew University of Jerusalem, Rehovot, Israel.
Sela
I
I
Galili
G
G
D000818:Animals; D001483:Base Sequence; D002458:Cell Fractionation; D002460:Cell Line; D003001:Cloning, Molecular; D004247:DNA / Q000235:genetics / Q000302:isolation & purification; D005347:Fibroblasts / Q000378:metabolism; D005786:Gene Expression Regulation; D006801:Humans; D016899:Interferon-beta / Q000096:biosynthesis / Q000235:genetics*; D007700:Kinetics; D008969:Molecular Sequence Data; D011061:Poly A / Q000235:genetics / Q000378:metabolism*; D011132:Polyribosomes / Q000378:metabolism; D014176:Protein Biosynthesis; D012313:RNA / Q000235:genetics / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism*; D011817:Rabbits; D015183:Restriction Mapping; D012156:Reticulocytes / Q000378:metabolism; D016914:Ribonuclease H; D014158:Transcription, Genetic; D014466:Ultraviolet Rays
D012333:RNA, Messenger; D011061:Poly A; D012313:RNA; D016899:Interferon-beta; D004247:DNA; D016914:Ribonuclease H