High-level ribosomal frameshifting directs the synthesis of IS150 gene products.
IS150 contains two tandem, out-of-phase, overlapping genes, ins150A and ins150B, which are controlled by the same promoter. These genes encode proteins of 19 and 31 kD, respectively. A third protein of 49 kD is a transframe gene product consisting of domains encoded by both genes. Specific -1 ribosomal frameshifting is responsible for the synthesis of the large protein. Expression of ins150B also involves frameshifting. The IS150 frameshifting signals operate with a remarkably high efficiency, causing about one third of the ribosomes to switch frame. All of the signals required for this process are encoded in a 83-bp segment of the element. The heptanucleotide A AAA AAG and a potential stem-loop-forming sequence mark the frameshifting site. Similar sequence elements are found in -1 frameshifting regions of bacterial and retroviral genes. A mutation within the stem-loop sequence reduces the rate of frameshifting by about 80%. Artificial transposons carrying this mutation transpose at a normal frequency, but form cointegrates at a approximately 100-fold reduced rate.
Vögele
K
K
Institut für Biologie III, Universität Freiburg, FRG.
Schwartz
E
E
Welz
C
C
Schiltz
E
E
Rak
B
B
D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000096:biosynthesis* / Q000235:genetics; D001483:Base Sequence; D004251:DNA Transposable Elements / Q000235:genetics / Q000502:physiology*; D004926:Escherichia coli / Q000235:genetics*; D029968:Escherichia coli Proteins; D015964:Gene Expression Regulation, Bacterial / Q000502:physiology; D005807:Genes, Overlapping; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D009690:Nucleic Acid Conformation; D016366:Open Reading Frames; D014176:Protein Biosynthesis / Q000502:physiology*; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis; D012091:Repetitive Sequences, Nucleic Acid / Q000235:genetics / Q000502:physiology; D012270:Ribosomes / Q000378:metabolism*
D001426:Bacterial Proteins; D004251:DNA Transposable Elements; D029968:Escherichia coli Proteins; C070719:INS150A protein, E coli; C070720:INS150B protein, E coli; D011993:Recombinant Fusion Proteins