Identification of the Escherichia coli sohB gene, a multicopy suppressor of the HtrA (DegP) null phenotype

Baird, Lisa; Lipińska, Barbara; Raina, Satish; Georgopoulos, Costa

doi:10.1128/jb.173.18.5763-5770.1991

Cited by 43 publications

(30 citation statements)

References 37 publications

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“…Another approach to characterizing the cellular functions of the wild-type genes which are mutated is to screen for multicopy suppressor genes (1,3,23,29). Very recently, we identified a multicopy suppressor gene of smbA mutation, named mssA, that maps at 21 min, just upstream of the rpsA gene on the E. coli chromosome (48).…”

Section: Suppressor Mutation Of the Mukb Null Mutantmentioning

confidence: 99%

Identification and characterization of the smbA gene, a suppressor of the mukB null mutant of Escherichia coli

et al. 1992

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The mukB gene encodes a protein involved in chromosome partitioning in Escherichia coli. To study the function of this protein, we isolated from the temperature-sensitive mukB null mutant and characterized 56 suppressor mutants which could grow at 42 degrees C. Ten of the mutants also showed cold-sensitive growth at 22 degrees C. Using one of the cold-sensitive mutants as host, the wild type of the suppressor gene was cloned. The cloned suppressor gene complemented all of the 56 suppressor mutations. DNA sequencing revealed the presence of an open reading frame of 723 bp which could encode a protein of 25,953 Da. The gene product was indeed detected. The previously undiscovered gene, named smbA (suppressor of mukB), is located at 4 min on the E. coli chromosome, between the tsf and frr genes. The smbA gene is essential for cell proliferation in the range from 22 to 42 degrees C. Cells which lacked the SmbA protein ceased macromolecular synthesis. The smbA mutants are sensitive to a detergent, sodium dodecyl sulfate, and they show a novel morphological phenotype under nonpermissive conditions, suggesting a defect in specific membrane sites.

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Section: Suppressor Mutation Of the Mukb Null Mutantmentioning

confidence: 99%

Identification and characterization of the smbA gene, a suppressor of the mukB null mutant of Escherichia coli

et al. 1992

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“…at 37 uC or in the presence of puromycin), we observed that our double mutant has a lower growth rate than the trmA-clpP mutant (data not shown). Alternatively, htrA suppressors might have arisen, as previously shown in Escherichia coli, where sohA and sohB are multi-copy suppressors of htrA (Baird & Georgopoulos, 1990;Baird et al, 1991).…”

mentioning

confidence: 99%

Construction and characterization of a Lactococcus lactis strain deficient in intracellular ClpP and extracellular HtrA proteases

Cortes-Perez

Poquet²,

Oliveira

et al. 2006

Microbiology

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A Lactococcus lactis strain deficient in both its major proteases, intracellular (ClpP) and extracellular (HtrA), was constructed and characterized. This strain, hereafter called clpP-htrA, could be obtained only by conjugation between a clpP donor strain and an htrA recipient strain in the NZ9000 context, allowing heterologous gene expression under the control of the NICE (nisin-controlled expression) system. The clpP-htrA double mutant showed both higher stress tolerance (e.g. high temperature and ethanol resistance) and higher viability than single clpP or htrA mutant strains. In addition, the secretion rate of two heterologous proteins (staphylococcal nuclease Nuc and Nuc-E7) was also higher in clpP-htrA than in the wild-type strain. This strain should be a useful host for high-level production and quality of stable heterologous proteins.

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“…Prc is a protease that processes the C terminus of FtsI (penicillinbinding protein 3) and is required for protection from combined thermal and osmotic stress (20). The sppA gene and probably the sohB gene encode homologous proteases that degrade signal peptides after their processing (4,22). Additionally, the outer membrane-bound protease OmpT (protease VII) is specific for substrates with paired basic residues (55).…”

mentioning

confidence: 99%

Multicopy suppressors of prc mutant Escherichia coli include two HtrA (DegP) protease homologs (HhoAB), DksA, and a truncated R1pA

Bass¹,

Gu²,

Christen³

1996

J Bacteriol

142

120

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We have isolated three multicopy suppressors of the conditional lethal phenotype of a prc (tsp) null strain of Escherichia coli. One of these suppressors included two novel putative protease genes in tandem that map to 3400 kb or 72.5 centisomes on the chromosome. We propose the names hhoA and hhoB, for htrA homolog, to denote that these genes encode proteins that are 58 and 35% identical, respectively, to the HtrA (DegP) serine protease and 36% identical to each other. The HhoA and HhoB proteins are predicted to be 455 and 355 amino acids, respectively, in length. The mature HhoA protein is periplasmic in location, and amino-terminal sequencing shows that it arises following cleavage of a 27-amino-acid signal peptide. Searches of the protein and DNA databases reveal a rapidly growing family of homologous genes in a variety of other bacteria, including several which are required for virulence in their host. Deletion of the hhoAB genes shows that they are not required for viability at high temperatures like the homologous htrA but grow more slowly than wild-type strains. A second multicopy prc suppressor is the dksA (dnaK suppressor) gene, which is also a multicopy suppressor of defects in the heat shock genes dnaK, dnaJ, and grpE. The dksA gene was independently isolated as a multicopy suppressor of a mukB mutation, which is required for chromosomal partitioning. A third dosage-dependent prc suppressor includes a truncated rare lipoprotein A (rlpA) gene.

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Identification of the Escherichia coli sohB gene, a multicopy suppressor of the HtrA (DegP) null phenotype

Cited by 43 publications

References 37 publications

Identification and characterization of the smbA gene, a suppressor of the mukB null mutant of Escherichia coli

Identification and characterization of the smbA gene, a suppressor of the mukB null mutant of Escherichia coli

Construction and characterization of a Lactococcus lactis strain deficient in intracellular ClpP and extracellular HtrA proteases

Multicopy suppressors of prc mutant Escherichia coli include two HtrA (DegP) protease homologs (HhoAB), DksA, and a truncated R1pA

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