title: Multicopy suppression: an approach to understanding intracellular functioning of the protein export system.
abstract: Escherichia coli genes were cloned onto a multicopy plasmid and selected by the ability to restore growth and protein export defects caused by a temperature-sensitive secY or secA mutation. When secA51 was used as the primary mutation, only clones carrying groE, which specifies the chaperonin class of heat shock protein, were obtained. Selection using secY24 yielded three major classes of genes. The first class encodes another heat shock protein, HtpG; the most frequently obtained second class encodes a neutral histonelike protein, H-NS; and the third class, msyB, encodes a 124-residue protein of which 38 residues are acidic amino acids. Possible mechanisms of suppression as well as the significance and limitations of the multicopy suppression approach are discussed.
authors.affiliation: Institute for Virus Research, Kyoto University, Japan.
authors.forename: C
authors.initials: C
authors.lastname: Ueguchi
authors.forename: K
authors.initials: K
authors.lastname: Ito
mesh_terms: D000595:Amino Acid Sequence; D001425:Bacterial Outer Membrane Proteins / Q000378:metabolism; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D001483:Base Sequence; D001693:Biological Transport, Active / Q000235:genetics; D018833:Chaperonins; D004268:DNA-Binding Proteins / Q000378:metabolism; D004926:Escherichia coli / Q000235:genetics*; D029968:Escherichia coli Proteins; D005816:Genetic Complementation Test; D018841:HSP90 Heat-Shock Proteins; D006360:Heat-Shock Proteins / Q000235:genetics* / Q000378:metabolism; D008969:Molecular Sequence Data; D005810:Multigene Family; D010957:Plasmids / Q000235:genetics; D011499:Protein Processing, Post-Translational; D013489:Suppression, Genetic
chemical_list: D001425:Bacterial Outer Membrane Proteins; D001426:Bacterial Proteins; D004268:DNA-Binding Proteins; D029968:Escherichia coli Proteins; C028715:GroE protein, E coli; C031908:H-NS protein, bacteria; D018841:HSP90 Heat-Shock Proteins; D006360:Heat-Shock Proteins; C489352:HtpG protein, E coli; C066720:HtpG protein, bacteria; C073124:msyB protein, E coli; D018833:Chaperonins