DNA methyltransferases of the cyanobacterium Anabaena PCC 7120

Matveyev, Andrey V.; Young, Kathryn T.; Meng, Andrew; Elhai, Jeff

doi:10.1093/nar/29.7.1491

Cited by 33 publications

(39 citation statements)

References 62 publications

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“…The predicted amino acid sequence of BceSII shows 29% to 30% amino acid sequence identity and 42% to 43% sequence similarity to HgiBI, HgiEI, and HgiCII REases with the recognition sequence G/GWCC (REBASE) (15). In addition, the bceSIIM gene sequence is very similar to the avaIIM gene sequence (27), with the known target site GGWCC. The bceSIIR gene-induced cell extracts produced a partial digestion pattern similar to that seen with AvaII digestion (see Fig.…”

Section: Resultsmentioning

confidence: 93%

Characterization of Type II and III Restriction-Modification Systems from Bacillus cereus Strains ATCC 10987 and ATCC 14579

Nugent

Kasamkattil

et al. 2011

Journal of Bacteriology

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The genomes of two Bacillus cereus strains (ATCC 10987 and ATCC 14579) have been sequenced. Here, we report the specificities of type II/III restriction (R) and modification (M) enzymes. Found in the ATCC 10987 strain, BceSI is a restriction endonuclease (REase) with the recognition and cut site CGAAG 24-25/27-28. BceSII is an isoschizomer of AvaII (G/GWCC). BceSIII cleaves at ACGGC 12/14. The BceSIII C terminus resembles the catalytic domains of AlwI, MlyI, and Nt.BstNBI. BceSIV is composed of two subunits and cleaves on both sides of GCWGC. BceSIV activity is strongly stimulated by the addition of cofactor ATP or GTP. The large subunit (R1) of BceSIV contains conserved motifs of NTPases and DNA helicases. The R1 subunit has no endonuclease activity by itself; it strongly stimulates REase activity when in complex with the R2 subunit. BceSIV was demonstrated to hydrolyze GTP and ATP in vitro. BceSIV is similar to CglI (GCSGC), and homologs of R1 are found in 11 sequenced bacterial genomes, where they are paired with specificity subunits. In addition, homologs of the BceSIV R1-R2 fusion are found in many sequenced microbial genomes. An orphan methylase, M.BceSV, was found to modify GCNGC, GGCC, CCGG, GGN NCC, and GCGC sites. A ParB-methylase fusion protein appears to nick DNA nonspecifically. The ATCC 14579 genome encodes an active enzyme Bce14579I (GCWGC). BceSIV and Bce14579I belong to the phospholipase D (PLD) family of endonucleases that are widely distributed among Bacteria and Archaea. A survey of type II and III restriction-modification (R-M) system genes is presented from sequenced B. cereus, Bacillus anthracis, and Bacillus thuringiensis strains. Bacillus cereus is a Gram-positive, soil-dwelling, aerobic bacterium. Food contaminated with some B. cereus strains can cause nausea, vomiting, and diarrhea in humans. Certain B. cereus strains produce a pore-forming toxin called CytK (CytK-1 and CytK-2), which is hemolytic and toxic toward human intestinal Caco-2 cells and Vero cells (16). The genomic DNA sequences of Bacillus cereus strains ATCC 10987 and ATCC 14579 (nonpathogenic, biosafety level 1 strains) have been published (32). Genomic analysis indicated that B. cereus ATCC 10987 is more similar to Bacillus anthracis Ames than to B. cereus ATCC 14579 (19,29,32). In addition, nine more Bacillus cereus genomes of pathogenic and nonpathogenic strains have been sequenced (GenBank genome database). An additional 22 B. cereus strains have been sequenced by the shotgun sequencing method (GenBank). Bioinformatic analysis of the 11 fully sequenced genomes indicated that B. cereus strain ATCC 10987 harbors the most restriction-modification (R-M) systems among the B. cereus strains, with four predicted complete R-M systems, including one partially characterized type III R-M system, one orphan 5-cytosine methyltransferase (C5 methyltransferase [MTase]), and one ParB-methylase fusion (see the REBASE database) (34). Only one type II R-M system was predicted for the ATCC 14579 strain.The primary biological function of ...

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Section: Resultsmentioning

confidence: 93%

Characterization of Type II and III Restriction-Modification Systems from Bacillus cereus Strains ATCC 10987 and ATCC 14579

Nugent

Kasamkattil

et al. 2011

Journal of Bacteriology

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“…However, because these genes are separated by 674 bp of noncoding sequence, it is very improbable that they are cotranscribed. Moreover, the genes 3Ј from alr3699 presumptively encode a defective PstI methylase and endonuclease (24), for which no role in synthesis of HEP is evident. Nonetheless, we sought to test experimentally whether all4160 and alr3699 play essential roles in heterocyst development or whether mutation of these genes has only a polar effect.…”

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confidence: 99%

Predicted Glycosyl Transferase Genes Located outside the HEP Island Are Required for Formation of Heterocyst Envelope Polysaccharide in Anabaena sp. Strain PCC 7120

Wang

Lechno‐Yossef²,

Gong

et al. 2007

J Bacteriol

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During maturation, heterocysts form an envelope layer of polysaccharide, called heterocyst envelope polysaccharide (HEP), whose synthesis depends on a cluster of genes, the HEP island, and on an additional, distant gene, hepB, or a gene immediately downstream from hepB. We show that HEP formation depends upon the predicted glycosyl transferase genes all4160 at a third locus and alr3699, which is adjacent to hepB and is cotranscribed with it. Mutations in the histidine kinase genes hepN and hepK appear to silence the promoter of hepB and incompletely down-regulate all4160.The filamentous nitrogen-fixing cyanobacterium Anabaena sp. strain PCC 7120 produces terminally differentiated cells, called heterocysts, when it is deprived of fixed nitrogen. These specialized cells are internally microoxic as a result of (i) cessation of oxygen production; (ii) intensification of respiration; and (iii) deposition of a thick envelope, comprising an outer polysaccharide layer and an inner glycolipid layer, that impedes the entry of oxygen (35). The glycolipid layer is the principal barrier to the entry of oxygen, whereas the polysaccharide layer is evidently required for the integrity of the glycolipid layer. The homogeneous layer of heterocyst envelope polysaccharide (HEP) has been chemically analyzed in two other Anabaena sp. strains and in a Cylindrospermum sp. strain. In those strains, HEP is composed of oligosaccharide repeating units whose mannose-(glucose) 3 backbone is decorated with side chains that are different in the different strains. In the Anabaena sp. strains, a highly similar polysaccharide was found in the envelopes of akinetes, a kind of spore. It was crudely estimated that, exclusive of regulatory genes, on the order of 20 genes are required for synthesis of the concatenated subunits (33).Through DNA microarray analysis and near-saturation transposon mutagenesis, numerous Anabaena sp. strain PCC 7120 open reading frames in the HEP island (genes alr2825 through alr2841) of the chromosome were found to be required specifically for formation of the envelope polysaccharide layer (7, 17). Mutants with mutations in the presumptively glycosyl transferase-encoding genes hepB (alr3698) (23, 36), alr3699, and all4160 (this study) that are distant from the HEP island in the genome also lack the polysaccharide layer. Regulation of HEP deposition depends upon signal transduction systems that comprise, at least, the histidine kinase HepN (11,26), the response regulator HenR (11), the serine/threonine kinase HepS (11), and the interacting two-component regulatory elements HepK and DevR A (39, 40). In addition, proteins Abp2 and Abp3 bind to the DNA sequence upstream of hepC, and inactivation of abp2 and abp3 greatly reduces the expression of hepA and hepC (20). abp2 and abp3 mutants, however, lack the glycolipid layer of the heterocyst envelope rather than the polysaccharide layer.In the 1,076 sites of insertion mapped in a transposon mutagenesis project screening for Fox Ϫ mutants (i.e., mutants unable to fix dinitrogen i...

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“…It was reported that methylase C specifically methylates the first cytosine of the sequence 5=-CGATCG-3=, which blocks restriction digestion from the PvuI and SgfI endonucleases (which recognizes 5=-GCGATCGC-3=) (38), while modification methylase M (Sll0729) methylates the first cytosine of the sequence 5=-GGCC-3= (37,39,40), which blocks restriction digestion from the restriction endonuclease HaeIII (38). We screened the sequence of the integrative plasmid pSPtK and found in total two 5=-CGATC G-3= sites and six of 5=-GGCC-3= sites along the DNA sequence of the integration fragment (Fig.…”

Section: Resultsmentioning

confidence: 99%

“…In this study, two cytosine-specific methylase genes, sll0729 (gene M) and slr0214 (gene C), were cloned from the chromosome of Synechocystis 6803 (37). Specifically, gene C from Synechocystis 6803 encodes a cytosine-specific methyltransferase that putatively targets the first cytosine of the PvuI site (5=-CGATCG-3=) (38), and gene M has been predicted to encode a cytosine-specific methyltransferase that recognizes and functions on the first cytosine of the sequence 5=-GGCC-3= (37,39,40). These two genes were cloned and coexpressed in E. coli strains harboring the integration plasmids, and the effects of premethylation of foreign DNA on the integrative transformation efficiency in Synechocystis 6803 was investigated.…”

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Premethylation of Foreign DNA Improves Integrative Transformation Efficiency in Synechocystis sp. Strain PCC 6803

Wang

Zhang

et al. 2015

Appl Environ Microbiol

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cRestriction digestion of foreign DNA is one of the key biological barriers against genetic transformation in microorganisms. To establish a high-efficiency transformation protocol in the model cyanobacterium, Synechocystis sp. strain PCC 6803 (Synechocystis 6803), we investigated the effects of premethylation of foreign DNA on the integrative transformation of this strain. In this study, two type II methyltransferase-encoding genes, i.e., sll0729 (gene M) and slr0214 (gene C), were cloned from the chromosome of Synechocystis 6803 and expressed in Escherichia coli harboring an integration plasmid. After premethylation treatment in E. coli, the integration plasmid was extracted and used for transformation of Synechocystis 6803. The results showed that although expression of methyltransferase M had little impact on the transformation of Synechocystis 6803, expression of methyltransferase C resulted in 11-to 161-fold-higher efficiency in the subsequent integrative transformation of Synechocystis 6803. Effective expression of methyltransferase C, which could be achieved by optimizing the 5= untranslated region, was critical to efficient premethylation of the donor DNA and thus high transformation efficiency in Synechocystis 6803. Since premethylating foreign DNA prior to transforming Synechocystis avoids changing the host genetic background, the study thus provides an improved method for high-efficiency integrative transformation of Synechocystis 6803.

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DNA methyltransferases of the cyanobacterium Anabaena PCC 7120

Cited by 33 publications

References 62 publications

Characterization of Type II and III Restriction-Modification Systems from Bacillus cereus Strains ATCC 10987 and ATCC 14579

Characterization of Type II and III Restriction-Modification Systems from Bacillus cereus Strains ATCC 10987 and ATCC 14579

Predicted Glycosyl Transferase Genes Located outside the HEP Island Are Required for Formation of Heterocyst Envelope Polysaccharide in Anabaena sp. Strain PCC 7120

Premethylation of Foreign DNA Improves Integrative Transformation Efficiency in Synechocystis sp. Strain PCC 6803

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