Cytosine-specific type II DNA methyltransferases

Lauster, Roland; Trautner, Thomas A.; Noyer-Weidner, Mario

doi:10.1016/0022-2836(89)90480-4

Cited by 219 publications

(94 citation statements)

References 30 publications

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“…Several sequences that are apparently conserved in RNA and DNA methylases have already been noted (e.g. Lauster et al, 1989;Ingrosso et al, 1989). One of these (Region I of Ingrosso et al, 1989) corresponds precisely to the sequence VLE/DXGXGXG found in EryG (a methyltransferase that catalyses the last step in the biosynthesis of erythromycin in Saccharopolyspora erythraea) and ErmE (an rRNA methyltransferase in the same organism) (Haydock et al, 1991).…”

Section: Sequence Comparison Of the Ubig Protein With Other Proteinsmentioning

confidence: 86%

Isolation and characterization of Escherichia coli mutants affected in aerobic respiration: the cloning and nucleotide sequence of ubiG: Identification of an S-adenosylmethionine-binding motif in protein, RNA, and small-molecule methyltransferases

Williams²,

Zamanian³

et al. 1992

Journal of General Microbiology

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We report the isolation and characterization of a mutant of Escherichia coli unable to grow aerobically on nonfermentable substrates, except for very slow growth on glycerol. The mutant contains cytochrome oxidases o and d, and grows anaerobically with alternative electron acceptors. Oxygen consumption rates of cell-free extracts were low relative to activities in an isogenic control strain, but were restored in vitro by adding ubiquinone-1 to cell-free extracts. Transformation with a cloned 2.8 kb ClaI-EcoRV fragment of chromosomal DNA restored the ability of this mutant (AN2571) to grow on succinate and also restored cellular quinone levels in this strain. The plasmid also complemented a previously isolated ubiG mutant (AN151) for aerobic growth on succinate. The nucleotide sequence revealed a 0.7kb portion of gyvA. Unidirectional nested deletions from this fragment and complementation analysis identified an open reading frame encoding a protein with a predicted molecular mass of 26-5 kDa. This gene (u6iG) encodes the enzyme 2-octaprenyl-3-methyl-5-hydroxy-6-methoxy-1,4-benzoquinone methyltransferase, which catalyses the terminal step in the biosynthesis of ubiquinone. The open reading frame is preceded by a putative Shine-Dalgarno sequence and followed by three palindromic unit sequences. Comparison of the inferred amino acid sequence of UbiG with the sequence of other S-adenosylmethionine (AdoMet)-dependent methyltransferases reveals a highly conserved AdoMet-binding region. The cloned 2.8 kb fragment also contains a sequence encoding the C-terminus of a protein with 42-44 % identity to fungal acetyl-CoA synthetases.

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Section: Sequence Comparison Of the Ubig Protein With Other Proteinsmentioning

confidence: 86%

Isolation and characterization of Escherichia coli mutants affected in aerobic respiration: the cloning and nucleotide sequence of ubiG: Identification of an S-adenosylmethionine-binding motif in protein, RNA, and small-molecule methyltransferases

Williams²,

Zamanian³

et al. 1992

Journal of General Microbiology

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“…Experimental evidence suggests that the first four conserved motifs (I, IV, VI and VIII), representing the N-terminal region of the protein, play a role in the enzymatic function whereas the last motif (X) is involved in recognition of the target nucleotide sequence in the genome (Posfai et al, 1989). These two regions of the protein are separated by a long variable region which is 80-120 aa for monospecific MTases and 200-300 aa for multispecific-specific MTases (Lauster et al, 1989;Lange et al, 1991).…”

Section: Discussionmentioning

confidence: 99%

Identification and characterization of the frog virus 3 DNA methyltransferase gene

Kaur¹,

Rohozinski

Goorha³

1995

Journal of General Virology

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Cytosine DNA methyltransferases (MTases) first recognize specific nucleotide sequences and then transfer a methyl group from S-adenosylmethionine to cytosine. This division of function is reflected in five highly conserved motifs shared by cytosine MTases. The region containing the first four motifs is responsible for the catalytic function whereas the region containing the fifth motif V provides specificity of binding to DNA. In at least one case, two separate proteins, one containing the first four motifs and the second containing the last motif combine to provide full functional activity. In the frog virus 3 (FV3) genome we have identified an open reading frame (ORF) whose deduced amino acid (aa) sequence contains motifs characteristic of prokaryotic as well as eukaryotic MTases. The ORF consists of 642 bp which codes for a protein of 214 aa with a predicted molecular mass of 24.8 kDa. This ORF contains the first four highly conserved motifs of cytosine MTases but the fifth motif, responsible for DNA binding specificity, is missing. Presumably, FV3 MTase is composed of two subunits. Northern blot analysis showed that the putative MTase ORF is transcribed into two transcripts belonging to the delayed-early class of FV3 messages. These two transcripts appear to be initiated at two different start sites but terminate in the same 3' region of the gene. The transcription start sites are not preceded by any known promoter sequences, but two regions of hyphenated dyad symmetry are present at the 3' end of the message. A protein with a molecular mass of ~ 28 kDa was synthesized by a rabbit reticulocyte lysate programmed with capped runoff transcripts from the cloned gene, suggesting that the ORF can be transcribed into a message coding for a viral protein. Overall, our results suggest that we have identified a gene for a subunit of MTase in the FV3 genome.

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“…Most have a C-terminal catalytic domain containing the 10 DNA methyltransferase signature sequence motifs found in procaryotes (Lauster et al, 1989;Posfai et al, 1989), and an N-terminal domain involved in proteinprotein interactions. DNMT1 has a preference for hemimethylated DNA and is required for maintenance of methylation patterns in embryos and adult tissues (Bestor et al, 1988;Li et al, 1992).…”

Section: Introductionmentioning

confidence: 99%

DNA methyltransferase 3b contributes to oncogenic transformation induced by SV40T antigen and activated Ras

2003

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Transcriptional silencing of tumor suppressor genes in association with DNA methylation contributes to malignant transformation. However, the specific DNA methyltransferases that initiate this process are unknown. Here we show that a de novo DNA methyltransferase, DNMT3b, substantially contributes to the oncogenic phenotype in a lung cancer model. Normal human bronchial epithelial (NHBE) cells expressing telomerase, SV40 large T antigen, and activated Ras were immortal, formed colonies in soft agar, and expressed DNMT3b. Antisense suppression of DNMT3b prevented soft agar growth. Furthermore, mouse embryo fibroblasts expressing T antigen and Ras formed soft agar colonies and large tumors, but fibroblasts from Dnmt3b À/À mice did not grow in soft agar and were much less tumorigenic in vivo. The tumor suppressor genes, FHIT, TSLC1, and RASSF1A were downregulated in transformed NHBE cells, and antisense DNMT3b treatment resulted in reexpression of FHIT and TSLC1. While expression of TSCL1 correlated with methylation of CpG dinucleotides in its promoter region, the expression of FHIT did not, suggesting that DNMT3b may silence genes by several mechanisms including direct DNA methylation or recruitment of proteins that modify chromatin. Regardless of mechanism, our data indicate that DNMT3b plays an important role in transformation.

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Cytosine-specific type II DNA methyltransferases

Cited by 219 publications

References 30 publications

Isolation and characterization of Escherichia coli mutants affected in aerobic respiration: the cloning and nucleotide sequence of ubiG: Identification of an S-adenosylmethionine-binding motif in protein, RNA, and small-molecule methyltransferases

Isolation and characterization of Escherichia coli mutants affected in aerobic respiration: the cloning and nucleotide sequence of ubiG: Identification of an S-adenosylmethionine-binding motif in protein, RNA, and small-molecule methyltransferases

Identification and characterization of the frog virus 3 DNA methyltransferase gene

DNA methyltransferase 3b contributes to oncogenic transformation induced by SV40T antigen and activated Ras

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