scholarly journals Inhibition of glycine cleavage system by pyridoxine 5′‐phosphate causes synthetic lethality in glyA yggS and serA yggS in Escherichia coli

2019 ◽  
Vol 113 (1) ◽  
pp. 270-284 ◽  
Author(s):  
Tomokazu Ito ◽  
Ran Hori ◽  
Hisashi Hemmi ◽  
Diana M. Downs ◽  
Tohru Yoshimura
Keyword(s):  
Escherichia Coli ◽  
Synthetic Lethality ◽  
Glycine Cleavage System ◽  
Glycine Cleavage

Cloning and nucleotide sequence of the gcv operon encoding the Escherichia coli glycine-cleavage system

1993 ◽  
Vol 216 (2) ◽  
pp. 539-548 ◽  
Author(s):  
Kazuko OKAMURA-IKEDA ◽  
Yosuke OHMURA ◽  
Kazuko FUJIWARA ◽  
Yutaro MOTOKAWA
Keyword(s):  
Escherichia Coli ◽  
Nucleotide Sequence ◽  
Glycine Cleavage System ◽  
Glycine Cleavage ◽  
Gcv Operon

scholarly journals Glycine Cleavage System and cAMP Receptor Protein Co-Regulate CRISPR/cas3 Expression to Resist Bacteriophage

Viruses ◽  
2020 ◽  
Vol 12 (1) ◽  
pp. 90
Author(s):  
Denghui Yang ◽  
Zhaofei Wang ◽  
Jingjiao Ma ◽  
Qiang Fu ◽  
Lifei Wu ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Receptor Protein ◽  
Type I ◽  
Glycine Cleavage System ◽  
Camp Receptor Protein ◽  
Regulatory Pathway ◽  
Camp Concentration ◽  
Methylene Tetrahydrofolate ◽  
Glycine Cleavage ◽  
Camp Receptor

The CRISPR/Cas system protects bacteria against bacteriophage and plasmids through a sophisticated mechanism where cas operon plays a crucial role consisting of cse1 and cas3. However, comprehensive studies on the regulation of cas3 operon of the Type I-E CRISPR/Cas system are scarce. Herein, we investigated the regulation of cas3 in Escherichia coli. The mutation in gcvP or crp reduced the CRISPR/Cas system interference ability and increased bacterial susceptibility to phage, when the casA operon of the CRISPR/Cas system was activated. The silence of the glycine cleavage system (GCS) encoded by gcvTHP operon reduced cas3 expression. Adding N5, N10-methylene tetrahydrofolate (N5, N10-mTHF), which is the product of GCS-catalyzed glycine, was able to activate cas3 expression. In addition, a cAMP receptor protein (CRP) encoded by crp activated cas3 expression via binding to the cas3 promoter in response to cAMP concentration. Since N5, N10-mTHF provides one-carbon unit for purine, we assumed GCS regulates cas3 through associating with CRP. It was evident that the mutation of gcvP failed to further reduce the cas3 expression with the crp deletion. These results illustrated a novel regulatory pathway which GCS and CRP co-regulate cas3 of the CRISPR/Cas system and contribute to the defence against invasive genetic elements, where CRP is indispensable for GCS regulation of cas3 expression.

scholarly journals Synthetic Lethality with the dut Defect in Escherichia coli Reveals Layers of DNA Damage of Increasing Complexity Due to Uracil Incorporation

2008 ◽  
Vol 190 (17) ◽  
pp. 5841-5854 ◽  
Author(s):  
Helen Ting ◽  
Elena A. Kouzminova ◽  
Andrei Kuzminov
Keyword(s):  
Escherichia Coli ◽  
Dna Repair ◽  
Metabolic Pathways ◽  
Synthetic Lethality ◽  
Nucleotide Metabolism ◽  
Genetic Interactions ◽  
Single Defect ◽  
Damage Repair ◽  
Mutant Combination ◽  
Dna Incorporation

ABSTRACT Synthetic lethality is inviability of a double-mutant combination of two fully viable single mutants, commonly interpreted as redundancy at an essential metabolic step. The dut-1 defect in Escherichia coli inactivates dUTPase, causing increased uracil incorporation in DNA and known synthetic lethalities [SL(dut) mutations]. According to the redundancy logic, most of these SL(dut) mutations should affect nucleotide metabolism. After a systematic search for SL(dut) mutants, we did identify a single defect in the DNA precursor metabolism, inactivating thymidine kinase (tdk), that confirmed the redundancy explanation of synthetic lethality. However, we found that the bulk of mutations interacting genetically with dut are in DNA repair, revealing layers of damage of increasing complexity that uracil-DNA incorporation sends through the chromosomal metabolism. Thus, we isolated mutants in functions involved in (i) uracil-DNA excision (ung, polA, and xthA); (ii) double-strand DNA break repair (recA, recBC, and ruvABC); and (iii) chromosomal-dimer resolution (xerC, xerD, and ftsK). These mutants in various DNA repair transactions cannot be redundant with dUTPase and instead reveal “defect-damage-repair” cycles linking unrelated metabolic pathways. In addition, two SL(dut) inserts (phoU and degP) identify functions that could act to support the weakened activity of the Dut-1 mutant enzyme, suggesting the “compensation” explanation for this synthetic lethality. We conclude that genetic interactions with dut can be explained by redundancy, by defect-damage-repair cycles, or as compensation.

Sign in / Sign up

Export Citation Format

Share Document