PMID:7748952

Citation	Tsui, HC and Winkler, ME (1994) Transcriptional patterns of the mutL-miaA superoperon of Escherichia coli K-12 suggest a model for posttranscriptional regulation.Biochimie 76:1168-77
Abstract	The complex amiB-mutL-miaA-hfq-hflX-hflK-hflC superoperon of E coli contains important genes for several fundamental cellular processes, including cell-wall hydrolysis (amiB), DNA repair (mutL), tRNA modification (miaA) and proteolysis (hflX-hflK-hflC). We report here the transcriptional pattern and possible posttranscriptional regulation of mutL, miaA and hfq genes of this superoperon. RNase protection analysis of mRNA transcribed from the bacterial chromosome demonstrated that there is co-transcription of mutL and miaA. In addition, two internal promoters, PmiaA and P1hfq were identified and mapped to 201 and 837 nucleotides upstream from the respective translation start sites. PmiaA contains poor matches to the -10 and -35 regions of the sigma-70 RNA polymerase consensus sequences, but it contains multiple potential Fis-binding sites and an upstream AT-rich region with poly(A) sequences. The basic arrangement of Fis-binding sites followed by an AT rich region is shared with promoters for rRNA operons and some of the tRNA and tRNA modification genes. As part of an initial study of mutL and miaA regulation, we measured transcript amounts in isogenic rne, rnc and rne rnc double mutants which are deficient in RNase E, RNase III or both. The amounts of steady state level mutL-miaA cotranscript, PmiaA transcript and P1hfq transcript increased eight-, nine- and three-fold respectively in an rne3071 mutant when compared to the rne+ parent. In contrast, amounts of the three transcripts were the same in an rnc105 mutant and its rnc+ parent. These results indicate that mutL, miaA, and hfq expression could be regulated by multiple mechanisms, including degree of cotranscription from upstream genes, modulation of internal promoter strength, and by RNase E activity. A model is presented for RNase E-mediated posttranscriptional regulation that may coordinate mutL expression with replication and miaA with tRNA amounts under different growth conditions, especially during nutrient upshifts.
Links	PubMed
Keywords	Amino Acid Sequence; Base Sequence; Cell Division; Codon; Escherichia coli; Gene Expression Regulation, Bacterial; Genes, Bacterial; Molecular Sequence Data; Operon; Promoter Regions, Genetic; Sequence Homology, Nucleic Acid; Transcription, Genetic
edit table

Main Points of the Paper

Please summarize the main points of the paper.

Materials and Methods Used

Please list the materials and methods used in this paper (strains, plasmids, antibodies, etc).

Phenotype Annotations

See Help:AnnotationTable for details on how to edit this table.
<protect>

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: Escherichia coli Strain: K-12 Substrain: N3431 NCBI Taxon ID: 83333	Genotype of Reference Strain: rne Genotype of Experimental Strain : rne3071	Reference Condition:	OMP:0000267	increased gene expression			This temperature sensitive mutation up regulates mutL-miaA which are co transcribed, and up regulates transcription of promoters Pmia and P1hfq by a factor of 3, 7 and 8 fold. Table 2.
a mutation or genetic difference within a strain	Taxon: Escherichia coli Strain: K-12 Substrain: TX2568 (Cmr) & TX2569 (Kmr) NCBI Taxon ID: 83333	Genotype of Reference Strain: mutL Genotype of Experimental Strain : mutL:omega(Kmr OR Cmr);BsaAI	Reference Condition:	OMP:0000253	gene expression phenotype			The polar omega cassettes blocked mutL-miaA transcription and caused the full-lengthened protected species to disappear, Fig. 2 lanes 3 and 4.
edit table

</protect>

References

See Help:References for how to manage references in omp dev.