PMID:7984093

Citation	Tsui, HC, Leung, HC and Winkler, ME (1994) Characterization of broadly pleiotropic phenotypes caused by an hfq insertion mutation in Escherichia coli K-12.Mol. Microbiol. 13:35-49
Abstract	The region immediately downstream from the miaA tRNA modification gene at 94.8 min contains the hfq gene and the hflA region, which are important in the bacteriophage Q beta and lambda life cycles. The roles of these genes in bacteria remain largely unknown. We report here the characterization of two chromosomal hfq insertion mutations. An omega (omega) cassette insertion near the end of hfq resulted in phenotypes only slightly different from the parent, although transcript mapping demonstrated that the insertion was completely polar on hflX expression. In contrast, an equally polar omega cassette insertion near the beginning of hfq caused pronounced pleiotropic phenotypes, including decreased growth rates and yields, decreased negative supercoiling of plasmids in stationary phase, increased cell size, osmosensitivity, increased oxidation of carbon sources, increased sensitivity to ultraviolet light, and suppression of bgl activation by hns mutations. hfq::omega mutant phenotypes were distinct from those caused by omega insertions early in the miaA tRNA modification gene. On the other hand, both hfq insertions interfered with lambda phage plaque formation, probably by means of polarity at the hflA region. Together, these results show that hfq function plays a fundamental role in Escherichia coli physiology and that hfq and the hflA-region are in the amiB-mutL-miaA-hfq-hflX superoperon.
Links	PubMed
Keywords	Alkyl and Aryl Transferases; Bacterial Proteins; Bacteriophage lambda; Base Sequence; Carrier Proteins; Chromosome Mapping; Coliphages; DNA, Recombinant; Escherichia coli; Escherichia coli Proteins; GTP-Binding Proteins; Gene Expression Regulation, Bacterial; Host Factor 1 Protein; Integration Host Factors; Membrane Proteins; Molecular Sequence Data; Mutagenesis, Insertional; Operon; Phenotype; Serine Endopeptidases; Transcription, Genetic; Transferases; Virus Replication
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Materials and Methods Used

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Phenotype Annotations

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Phenotype of	Taxon Information	Genotype Information (if known)	Condition Information	OMP ID	OMP Term Name	ECO ID	ECO Term Name	Notes	Status
a mutation or genetic difference within a strain	Taxon: Esch Strain: K-12 Substrain: MG1655 NCBI Taxon ID: 51145	Genotype of Reference Strain: hfq+ Genotype of Experimental Strain : hfq1::omega	Reference Condition:	0000280	increased cell length			The mutation was an insertion of a omega cassette near the start of hfq sequence of this strain. Causing change in cell shape, specifically, elongation of the cells.
a mutation or genetic difference within a strain	Taxon: Escherichia coli Strain: K-12 Substrain: MG1655 NCBI Taxon ID: 511145	Genotype of Reference Strain: hfq+ Genotype of Experimental Strain : "'hfq::omega	Reference Condition:					There was an Insertion of a omega cassette near the start of hfq sequence of the strain, causing a decrease in the strains growth rate and overall yield.
a mutation or genetic difference within a strain	Taxon: Escherichia coli Strain: MG1655 Substrain: 51145	Genotype of Reference Strain: hfq+ Genotype of Experimental Strain : "'hfq::omega	Reference Condition:					An omega cassette was inserted towards the start of the hfq sequence causing a change in cell shape, specifically a relaxation of the supercoiling.
a single strain under different conditions	Taxon: Escherichia coli Strain: K-12 Substrain: MG1655 NCBI Taxon ID: 51145	Genotype of Reference Strain: hfq+ Genotype of Experimental Strain : "'hfq::omega	Reference Condition:					An omega cassette was inserted near the start of the hfq sequence causingspontaneous mutagenesis.
a mutation or genetic difference within a strain	Taxon: Escherichia coli Strain: MG1655 Substrain: 511145	Genotype of Reference Strain: hfq+ Genotype of Experimental Strain : hfq1::omega	Reference Condition:					The mutation was the insertion of a omega cassette near the beginning of the hfq sequence of the strain causing a sensitivity to Ultraviolet light.
a mutation or genetic difference within a strain	Taxon: Escherichia coli Strain: MG1655 Substrain: 511145	Genotype of Reference Strain: hfq+ Genotype of Experimental Strain : "'hfq::omega	Reference Condition:					The insertion of an omega cassette near the start of the hfq sequence caused an increase in the oxidation of various carbon sources.
a mutation or genetic difference within a strain	Taxon: Escherichia coli Strain: MG1655 Substrain: 511145	Genotype of Reference Strain: hfq+ Genotype of Experimental Strain : hfq1::omega	Reference Condition:					This mutation involved the insertion of a omega cassette near the end of the hfq sequence. It resulted in no substantial difference from hfq+ parent strain.
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