Constitutive SOS expression and damage‐inducible AddAB‐mediated recombinational repair systems for <i>Coxiella burnetii</i> as potential adaptations for survival within macrophages

Mertens, Katja; Lantsheer, Letty; Ennis, Don G.; Samuel, James E.

doi:10.1111/j.1365-2958.2008.06373.x

Cited by 36 publications

(27 citation statements)

References 74 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Consistently, induction of DNA damage does not increase the expression of DNA repair genes, including HprecA, but rather that of genes coding for the competence machinery components (7). The induction of competence by genotoxic agents was previously reported for other pathogens, such as Streptococcus pneumoniae (5), Coxiella burnetii (20), and Legionella pneumophila (4). Induction of competence genes instead of the SOS system, absent in these organisms, may then be an adaptation to pathogenicity.…”

Section: Discussionmentioning

confidence: 52%

Biochemical and Cellular Characterization of Helicobacter pylori RecA, a Protein with High-Level Constitutive Expression

2011

View full text Add to dashboard Cite

Helicobacter pylori is a bacterial pathogen colonizing half of the world's human population. It has been implicated in a number of gastric diseases, from asymptomatic gastritis to cancer. It is characterized by an amazing genetic variability that results from high mutation rates and efficient DNA homologous recombination and transformation systems. Here, we report the characterization of H. pylori RecA (HpRecA), a protein shown to be involved in DNA repair, transformation, and mouse colonization. The biochemical characterization of the purified recombinase reveals activities similar to those of Escherichia coli RecA (EcRecA). We show that in H. pylori, HpRecA is present in about 80,000 copies per cell during exponential growth and decreases to about 50,000 copies in stationary phase. The amount of HpRecA remains unchanged after induction of DNA lesions, suggesting that HpRecA is always expressed at a high level in order to repair DNA damage or facilitate recombination. We performed HpRecA localization analysis by adding a Flag tag to the protein, revealing two different patterns of localization. During exponential growth, RecA-Flag presents a diffuse pattern, overlapping with the DAPI (4,6-diamidino-2-phenylindole) staining of DNA, whereas during stationary phase, the protein is present in more defined areas devoid of DAPI staining. These localizations are not affected by inactivation of competence or DNA recombination genes. Neither UV irradiation nor gamma irradiation modified HpRecA localization, suggesting the existence of a constitutive DNA damage adaptation system.

show abstract

Section: Discussionmentioning

confidence: 52%

Biochemical and Cellular Characterization of Helicobacter pylori RecA, a Protein with High-Level Constitutive Expression

2011

View full text Add to dashboard Cite

show abstract

“…Searches via BLASTP of these 26 strains with the LexA sequence of E. coli as well as the more closely related Pseudomonas aeruginosa yielded hits only to umuDAb-and umuD-encoded proteins, in spite of genes annotated as lexA in six Acinetobacter species. The absence of LexA, while not common, has been observed in diverse bacteria such as Mycoplasma, Chlamydia, Borrelia, Helicobacter and Coxiella (Campoy et al, 2002;Mertens et al, 2008), and shows that alternative mechanisms of regulating responses to DNA damage exist in bacteria.…”

Section: Resultsmentioning

confidence: 99%

Diverse responses to UV light exposure in Acinetobacter include the capacity for DNA damage-induced mutagenesis in the opportunistic pathogens Acinetobacter baumannii and Acinetobacter ursingii

et al. 2012

View full text Add to dashboard Cite

Error-prone and error-free DNA damage repair responses that are induced in most bacteria after exposure to various chemicals, antibiotics or radiation sources were surveyed across the genus Acinetobacter. The error-prone SOS mutagenesis response occurs when DNA damage induces a cell's umuDC-or dinP-encoded error-prone polymerases. The model strain Acinetobacter baylyi ADP1 possesses an unusual, regulatory umuD allele (umuDAb) with an extended 59 region and only incomplete fragments of umuC. Diverse Acinetobacter species were investigated for the presence of umuDC and their ability to conduct UV-induced mutagenesis. Unlike ADP1, most Acinetobacter strains possessed multiple umuDC loci containing either umuDAb or a umuD allele resembling that of Escherichia coli. The nearly omnipresent umuDAb allele was the ancestral umuD in Acinetobacter, with horizontal gene transfer accounting for over half of the umuDC operons. Despite multiple umuD(Ab)C operons in many strains, only three species conducted UV-induced mutagenesis: Acinetobacter baumannii, Acinetobacter ursingii and Acinetobacter beijerinckii. The type of umuDC locus or mutagenesis phenotype a strain possessed was not correlated with its error-free response of survival after UV exposure, but similar diversity was apparent. The survival of 30 Acinetobacter strains after UV treatment ranged over five orders of magnitude, with the Acinetobacter calcoaceticus-A. baumannii (Acb) complex and haemolytic strains having lower survival than non-Acb or non-haemolytic strains. These observations demonstrate that a genus can possess a range of DNA damage response mechanisms, and suggest that DNA damage-induced mutation could be an important part of the evolution of the emerging pathogens A. baumannii and A. ursingii. INTRODUCTIONWhen bacteria are exposed to DNA-damaging agents, such as UV light or chemical mutagens, a wide variety of SOS response genes (genes that play critical roles in repairing damaged DNA) are specifically induced (Friedberg et al., 1995;Walker, 1996). In the model developed by experimentation in Escherichia coli, SOS genes are negatively regulated by the LexA repressor binding to the SOS box in the promoter (Mount et al., 1972). DNA damage causes the activation of RecA, which facilitates LexA self-cleavage and releases the repression of SOS genes such as umuDC (Little et al., 1980;1981). UmuD initially causes a pause in cell division while DNA repair and replication occurs (Opperman et al., 1999). However, within minutes, UmuD homodimerizes and carries out intermolecular self-cleavage, facilitated by activated RecA* interaction (Nohmi et al., 1988). Two cleaved UmuD9 molecules then associate with UmuC to form DNA polymerase V, which carries out error-prone, trans-lesion DNA replication (SOS mutagenesis) (Reuven et al., 1999;Tang et al., 1999). Another errorprone polymerase commonly involved in SOS mutagenesis as part of the DNA damage response is DinP (also called DinB), DNA polymerase IV, which can function either by itself (Kim et al., 1997) or with U...

show abstract

“…An alternative class of enzymes, the AddAB family (also referred to as RexAB), was originally thought to fulfill the same break-processing function in a restricted niche of gram-positive bacteria (57,59,60,101,118). However, AddAB-type complexes are now appreciated to be more prevalent, having also been found widely in the proteobacteria (3,203,234,328). Like RecBCD, the AddAB enzyme is implicated in recombinational repair, and the inactivation of either subunit renders cells sensitive to DNA damage and reduces viability.…”

Section: The Addab Family Of Helicase-nuclease Enzymes Primary Structmentioning

confidence: 99%

RecBCD Enzyme and the Repair of Double-Stranded DNA Breaks

Dillingham

Kowalczykowski

2008

Microbiol Mol Biol Rev

507

599

View full text Add to dashboard Cite

SUMMARY The RecBCD enzyme of Escherichia coli is a helicase-nuclease that initiates the repair of double-stranded DNA breaks by homologous recombination. It also degrades linear double-stranded DNA, protecting the bacteria from phages and extraneous chromosomal DNA. The RecBCD enzyme is, however, regulated by a cis-acting DNA sequence known as Chi (crossover hotspot instigator) that activates its recombination-promoting functions. Interaction with Chi causes an attenuation of the RecBCD enzyme's vigorous nuclease activity, switches the polarity of the attenuated nuclease activity to the 5′ strand, changes the operation of its motor subunits, and instructs the enzyme to begin loading the RecA protein onto the resultant Chi-containing single-stranded DNA. This enzyme is a prototypical example of a molecular machine: the protein architecture incorporates several autonomous functional domains that interact with each other to produce a complex, sequence-regulated, DNA-processing machine. In this review, we discuss the biochemical mechanism of the RecBCD enzyme with particular emphasis on new developments relating to the enzyme's structure and DNA translocation mechanism.

show abstract

Constitutive SOS expression and damage‐inducible AddAB‐mediated recombinational repair systems for Coxiella burnetii as potential adaptations for survival within macrophages

Cited by 36 publications

References 74 publications

Biochemical and Cellular Characterization of Helicobacter pylori RecA, a Protein with High-Level Constitutive Expression

Biochemical and Cellular Characterization of Helicobacter pylori RecA, a Protein with High-Level Constitutive Expression

Diverse responses to UV light exposure in Acinetobacter include the capacity for DNA damage-induced mutagenesis in the opportunistic pathogens Acinetobacter baumannii and Acinetobacter ursingii

RecBCD Enzyme and the Repair of Double-Stranded DNA Breaks

Contact Info

Product

Resources

About