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TOP mRNAs are translationally inhibited by a titratable repressor in both wheat germ extract and reticulocyte lysate
Author(s) -
Biberman Yael,
Meyuhas Oded
Publication year - 1999
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/s0014-5793(99)00983-7
Subject(s) - repressor , ribosome , reticulocyte , biology , translation (biology) , messenger rna , protein biosynthesis , eukaryotic translation , microbiology and biotechnology , translational regulation , activator (genetics) , ribosomal binding site , rna , genetics , gene expression , gene
Vertebrate TOP mRNAs contain a 5′ terminal oligopyrimidine tract (5′ TOP), which is subject to selective translational repression in non‐growing cells or in cell‐free translation systems. In the present study, we monitored in vitro the effect of increasing amounts of a 16 nucleotides long oligoribonucleotide representing the 5′ terminus of mouse ribosomal protein S16 mRNA on the translation of TOP and non‐TOP mRNAs. Our results demonstrate that the wild‐type sequence (but not its mutant counterparts) derepresses the translation of mRNAs containing 5′ TOP motifs, but failed to stimulate the translation of non‐TOP mRNAs, even if the latter differed only by a single nucleotide from their 5′ TOP‐containing counterparts. Similar results have been obtained with both wheat germ extract and rabbit reticulocyte lysate. It appears, therefore, that translational repression of TOP mRNAs is achieved in vitro by the accumulation of a titratable repressor rather than by the loss of an activator and that this repressor recognizes multiple TOP mRNAs with a diverse set of 5′ TOP motifs.