Characterization of the 5-hydroxymethylcytosine-specific DNA restriction endonucleases
| Autor: | Zhenyu Zhu, Janine G. Borgaro |
|---|---|
| Rok vydání: | 2013 |
| Předmět: |
Cleavage (embryo)
Restriction fragment Substrate Specificity chemistry.chemical_compound Cytosine Restriction map Genetics Bacteriophage T4 DNA Cleavage chemistry.chemical_classification 5-Hydroxymethylcytosine biology Sequence Homology Amino Acid Nucleic Acid Enzymes DNA Restriction Enzymes Molecular biology Restriction enzyme Enzyme chemistry Biochemistry Glucosyltransferases DNA Viral biology.protein 5-Methylcytosine DNA |
| Zdroj: | Nucleic Acids Research |
| ISSN: | 1362-4962 |
| Popis: | In T4 bacteriophage, 5-hydroxymethylcytosine (5hmC) is incorporated into DNA during replication. In response, bacteria may have developed modification-dependent type IV restriction enzymes to defend the cell from T4-like infection. PvuRts1I was the first identified restriction enzyme to exhibit specificity toward hmC over 5-methylcytosine (5mC) and cytosine. By using PvuRts1I as the original member, we identified and characterized a number of homologous proteins. Most enzymes exhibited similar cutting properties to PvuRts1I, creating a double-stranded cleavage on the 3′ side of the modified cytosine. In addition, for efficient cutting, the enzymes require two cytosines 21–22-nt apart and on opposite strands where one cytosine must be modified. Interestingly, the specificity determination unveiled a new layer of complexity where the enzymes not only have specificity for 5-β-glucosylated hmC (5βghmC) but also 5-α-glucosylated hmC (5αghmC). In some cases, the enzymes are inhibited by 5βghmC, whereas in others they are inhibited by 5αghmC. These observations indicate that the position of the sugar ring relative to the base is a determining factor in the substrate specificity of the PvuRts1I homologues. Lastly, we envision that the unique properties of select PvuRts1I homologues will permit their use as an additive or alternative tool to map the hydroxymethylome. |
| Databáze: | OpenAIRE |
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