A thermosensitivepdxJ mutation affecting vitamin B6 biosynthesis inEscherichia coli K-12

Apostolakos, Diane; Birge, Edward A.

doi:10.1007/bf02601732

Cited by 11 publications

(4 citation statements)

References 13 publications

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“…1). Other linkage frequencies (data not shown) for putrL and nadB agreed with this order and with frequencies published by others (3,25,54 between a PstI site and a HincII site that lay 85 and 28 bp, respectively, upstream of the rnc translational start site. Therefore, these insertions mapped outside of the structural rnc gene yet appeared to block expression of RNase III.…”

supporting

confidence: 88%

Genetic analysis of the rnc operon of Escherichia coli

1989

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RNase III, an Escherichia coli double-stranded endoribonuclease, is known to be involved in maturation of rRNA and regulation of several bacteriophage and Escherichia coli genes. Clones of the region of the E. coli chromosome containing the gene for RNase III (rnc) were obtained by screening genomic libraries in A with DNA known to map near rnc. A phage clone with the rnc region was randomly mutagenized with a ATnJO element, and the insertions were recombined onto the chromosome, generating a series of strains with ATn10 insertions in the rnc region. Two insertions that had Rnc-phenotypes were located. One of them lay in the rnc gene, and one was in the rnc leader sequence. Polarity studies showed that rnc is in an operon with two other genes, era and recO. The sequence of the recO gene beyond era indicated it could encode a protein of -26 kilodaltons and, like rnc and era, had codon usage consistent with a low level of expression. Experiments using antibiotic cassettes to disrupt the genes rnc, era, and recO showed that era is essential for E. coli growth but that rnc and recO are dispensable.RNase III is an Escherichia coli endoribonuclease that cleaves specific double-stranded RNA structures (12,17). It is known to initiate maturation of rRNA from 30S precursor RNA (11,49) and has been implicated in the posttranscriptional processing of the mRNA transcripts of the early genes of bacteriophage T7 (15) Auxotrophs were screened on M56 glucose minimal plates. Each plate was spread with 100 ,ul of hypoxanthine (7.5 mg/ml; purl), glycine (1%; glyA), or nicotinic acid (0.25%; nadB), as appropriate. Antibiotics were used in the following final concentrations (micrograms per milliliter):ampicillin, 50; kanamycin, 25; chloramphenicol, 10; and tetracycline, 12.5. For growth of tetracycline-dependent (Tetd) strains in liquid medium, tetracycline was used at 3.0 ,ug/ml. Development of lambda clones and recombinants. Two different lambda phage libraries of the E. coli genome

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supporting

confidence: 88%

Genetic analysis of the rnc operon of Escherichia coli

1989

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“…The tentative gene order in this region is purL azl rnc lep pdxJ nadB (2). The gene lepA is not purL, pdxJ, or nadB because the AlepA mutation does not cause auxotrophy (1). Mutations at azl cause resistance to azaleucine (18).…”

Section: Discussionmentioning

confidence: 99%

lep operon proximal gene is not required for growth or secretion by Escherichia coli

Dibb¹,

Wolfe²

1986

J Bacteriol

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Leader peptidase is an essential enzyme of Escherichia coli and is required for protein export. The structural gene for leader peptidase (lep) is separated from its promoter by an upstream gene of unknown function (lepA). The gene lepA was shown by the use of minicell analysis and overproduction to encode a protein of 74,000 daltons. To determine whether this 74,000-dalton protein functions in protein export, a mutant of E. coli H560 was constructed which has a 1.5-kilobase-pair deletion in the lepA gene. The lepA deletion mutant had no apparent defect for growth or protein export, indicating that lepA is nonessential and that the two cotranscribed genes lepA and lep probably have unrelated functions.

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“…The importance of the de novo pathway is emphasized by various studies in E. coli , Streptococcus pneumonia , Bacillus subtilis , yeast, and plants where its complete loss is lethal to the organism, but can be rescued by an exogenous supply of the vitamin [ 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 ]. Even a reduction in the biosynthetic efficiency causes severe developmental problems.…”

Section: Introductionmentioning

confidence: 99%

Vitamin B6 and Its Role in Cell Metabolism and Physiology

Parra

Stahl

Hellmann

2018

Cells

300

159

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Vitamin B6 is one of the most central molecules in cells of living organisms. It is a critical co-factor for a diverse range of biochemical reactions that regulate basic cellular metabolism, which impact overall physiology. In the last several years, major progress has been accomplished on various aspects of vitamin B6 biology. Consequently, this review goes beyond the classical role of vitamin B6 as a cofactor to highlight new structural and regulatory information that further defines how the vitamin is synthesized and controlled in the cell. We also discuss broader applications of the vitamin related to human health, pathogen resistance, and abiotic stress tolerance. Overall, the information assembled shall provide helpful insight on top of what is currently known about the vitamin, along with addressing currently open questions in the field to highlight possible approaches vitamin B6 research may take in the future.

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A thermosensitivepdxJ mutation affecting vitamin B6 biosynthesis inEscherichia coli K-12

Cited by 11 publications

References 13 publications

Genetic analysis of the rnc operon of Escherichia coli

Genetic analysis of the rnc operon of Escherichia coli

lep operon proximal gene is not required for growth or secretion by Escherichia coli

Vitamin B6 and Its Role in Cell Metabolism and Physiology

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