Overexpression of the yeast HAM1 gene prevents 6-N-hydroxylaminopurine mutagenesis in Escherichia coli.

Kozmin, Stanislav G.; Leroy, Prune; Pavlov, Youri I.

doi:10.18388/abp.1998_4202

Cited by 9 publications

(8 citation statements)

References 9 publications

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“…Carlsson et al () have previously shown that overexpression of the Ham1 gene in yeast protects against the exogenous supply of the non‐canonical, mutagenic pyrimidine nucleoside 5‐fluorouracil (5‐FU). The yeast Ham1 gene can protect against several non‐canonical nucleosides, including 6‐ N ‐hydroxylaminopurine (Kozmin et al , ; Noskov et al , ), 5‐fluorocytosine, and 6‐azauracil (Carlsson et al , ). To investigate whether U/CBSV Ham1 proteins can also provide protection from 5‐FU, resistance assays were performed.…”

Section: Resultsmentioning

confidence: 99%

Cassava brown streak virus Ham1 protein hydrolyses mutagenic nucleotides and is a necrosis determinant

Tomlinson

Pablo‐Rodriguez

Bunawan

et al. 2019

Molecular Plant Pathology

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Summary Cassava brown streak disease (CBSD) is a leading cause of cassava losses in East and Central Africa, and is currently having a severe impact on food security. The disease is caused by two viruses within the Potyviridae family: Cassava brown streak virus (CBSV) and Ugandan cassava brown streak virus (UCBSV), which both encode atypical Ham1 proteins with highly conserved inosine triphosphate (ITP) pyrophosphohydrolase (ITPase) domains. ITPase proteins are widely encoded by plant, animal, and archaea. They selectively hydrolyse mutagenic nucleotide triphosphates to prevent their incorporation into nucleic acid and thereby function to reduce mutation rates. It has previously been hypothesized that U/CBSVs encode Ham1 proteins with ITPase activity to reduce viral mutation rates during infection. In this study, we investigate the potential roles of U/CBSV Ham1 proteins. We show that both CBSV and UCBSV Ham1 proteins have ITPase activities through in vitro enzyme assays. Deep‐sequencing experiments found no evidence of the U/CBSV Ham1 proteins providing mutagenic protection during infections of Nicotiana hosts. Manipulations of the CBSV_Tanza infectious clone were performed, including a Ham1 deletion, ITPase point mutations, and UCBSV Ham1 chimera. Unlike severely necrotic wild‐type CBSV_Tanza infections, infections of Nicotiana benthamiana with the manipulated CBSV infectious clones do not develop necrosis, indicating that that the CBSV Ham1 is a necrosis determinant. We propose that the presence of U/CBSV Ham1 proteins with highly conserved ITPase motifs indicates that they serve highly selectable functions during infections of cassava and may represent a euphorbia host adaptation that could be targeted in antiviral strategies.

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Section: Resultsmentioning

confidence: 99%

Cassava brown streak virus Ham1 protein hydrolyses mutagenic nucleotides and is a necrosis determinant

Tomlinson

Pablo‐Rodriguez

Bunawan

et al. 2019

Molecular Plant Pathology

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“…One CDS in pBKRR.14 matched with a periplasmic component of the Tol biopolymer transport system (Eick‐Helmerich and Braun, 1989). pBKRR.09 contained two coding sequences resembling a Ham1 family protein and a xenobiotic responsive element (XRE‐like protein) from the anaerobic archaea Sulfolobus solfataricus and Pyrococcus horikosh , which are involved in the protection of prokaryotic and eukaryotic organisms from toxic and mutagenic chemicals (Kozmin et al ., 1998), and in the expression of cytochrome P450 in response to xenobiotic inducers and dioxin respectively (Jones et al ., 1985; Fujisawa‐Sehara et al ., 1986).…”

Section: Resultsmentioning

confidence: 99%

Novel hydrolase diversity retrieved from a metagenome library of bovine rumen microflora

Ferrer

Golyshina

Chernikova

et al. 2005

Environmental Microbiology

258

145

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A metagenome expression library of bulk DNA extracted from the rumen content of a dairy cow was established in a phage lambda vector and activity-based screening employed to explore the functional diversity of the microbial flora. Twenty-two clones specifying distinct hydrolytic activities (12 esterases, nine endo-beta-1,4-glucanases and one cyclodextrinase) were identified in the library and characterized. Sequence analysis of the retrieved enzymes revealed that eight (36%) were entirely new and formed deep-branched phylogenetic lineages with no close relatives among known ester- and glycosyl-hydrolases. Bioinformatic analyses of the hydrolase gene sequences, and the sequences and contexts of neighbouring genes, suggested tentative phylogenetic assignments of the rumen organisms producing the retrieved enzymes. The phylogenetic novelty of the hydrolases suggests that some of them may have potential for new applications in biocatalysis.

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“…In E. coli , HAP hypersensitivity was observed in strains carrying a deletion of the uvrB‐bio chromosomal region (Pavlov et al ., 1996). The Δ( uvrB‐bio ) strains were also AHAP‐hypermutable and sensitive to growth inhibition or killing by hydroxylamine (Pavlov et al ., 1996; Kozmin et al ., 1998b). Likewise, Salmonella strains carrying a corresponding deletion of the uvrB‐bio region proved hypermutable by AHAP and N 4 ‐hydroxycytidine (Janion, 1978; Janion, 1979; Janion and Myszkowska, 1981).…”

Section: Introductionmentioning

confidence: 99%

YcbX and yiiM, two novel determinants for resistance of Escherichia coli to N‐hydroxylated base analogues

Kozmin

Leroy

Pavlov³

et al. 2008

Molecular Microbiology

104

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SummaryWe have shown previously that lack of molybdenum cofactor (MoCo) in Escherichia coli leads to hypersensitivity to the mutagenic and toxic effects of N-hydroxylated base analogues, such as 6-Nhydroxylaminopurine (HAP). However, the nature of the MoCo-dependent mechanism is unknown, as inactivation of all known and putative E. coli molybdoenzymes does not produce any sensitivity. Presently, we report on the isolation and characterization of two novel HAP-hypersensitive mutants carrying defects in the ycbX or yiiM open reading frames. Genetic analysis suggests that the two genes operate within the MoCo-dependent pathway. In the absence of the ycbX-and yiiM-dependent pathways, biotin sulfoxide reductase plays also a role in the detoxification pathway. YcbX and YiiM are hypothetical members of the MOSC protein superfamily, which contain the C-terminal domain (MOSC) of the eukaryotic MoCo sulphurases. However, deletion of ycbX or yiiM did not affect the activity of human xanthine dehydrogenase expressed in E. coli, suggesting that the role of YcbX and YiiM proteins is not related to MoCo sulphuration. Instead, YcbX and YiiM may represent novel MoCo-dependent enzymatic activities. We also demonstrate that the MoCo/YcbX/YiiM-dependent detoxification of HAP proceeds by reduction to adenine.

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Overexpression of the yeast HAM1 gene prevents 6-N-hydroxylaminopurine mutagenesis in Escherichia coli.

Cited by 9 publications

References 9 publications

Cassava brown streak virus Ham1 protein hydrolyses mutagenic nucleotides and is a necrosis determinant

Cassava brown streak virus Ham1 protein hydrolyses mutagenic nucleotides and is a necrosis determinant

Novel hydrolase diversity retrieved from a metagenome library of bovine rumen microflora

YcbX and yiiM, two novel determinants for resistance of Escherichia coli to N‐hydroxylated base analogues

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