Ribosomal protein S1 of Escherichia coli is the effector for the regulation of its own synthesis.
To facilitate the study of the regulation of the rpsA gene, a translational fusion between the rpsA gene and the lacZ gene was constructed. Synthesis of the fusion protein was repressed about 10-fold when rpsA was supplied in trans on a multicopy plasmid. This repression is similar to the post-transcriptional regulation previously found for the wild type rpsA gene. Addition of purified protein S1 to a coupled in vitro transcription-translation system caused a specific reduction in the synthesis of the rpsA-lacZ fusion protein. Addition of various subdomain fragments of protein S1 to the coupled in vitro system showed that the N-terminal fragment, possessing the ribosome binding domain of protein S1, was able to repress the synthesis of the rpsA-lacZ fusion protein. In contrast, fragments from the C-terminal region, containing the nucleic acid binding domain of protein S1, were inactive in this repression. Induction of truncated rpsA genes, coding for either the N-terminal 101 or 329 amino acids caused a reduction in the synthesis of the chromosomally encoded protein S1, thus confirming in vivo that the N-terminal part of protein S1 represses rpsA expression.
Skouv
J
J
Institute of Microbiology, University of Copenhagen, Denmark.
Schnier
J
J
Rasmussen
M D
MD
Subramanian
A R
AR
Pedersen
S
S
D000595:Amino Acid Sequence; D001483:Base Sequence; D004926:Escherichia coli / Q000235:genetics* / Q000378:metabolism; D015964:Gene Expression Regulation, Bacterial; D005798:Genes, Bacterial; D007700:Kinetics; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D010957:Plasmids; D014176:Protein Biosynthesis; D012333:RNA, Messenger / Q000235:genetics; D015183:Restriction Mapping; D012269:Ribosomal Proteins / Q000096:biosynthesis / Q000235:genetics* / Q000378:metabolism; D001616:beta-Galactosidase / Q000235:genetics / Q000378:metabolism
D012333:RNA, Messenger; D012269:Ribosomal Proteins; C015494:ribosomal protein S1; D001616:beta-Galactosidase