New England Biolabs, Inc.

Zhiyi Sun

Shengxi Guan

Theodore B Davis

Romualdas Vaisvila

Laurence Ettwiller

Lana Saleh

Zhenyu Zhu

Aine Quimby

Janine Borgaro

Methods and compositions are provided for identifying any of the presence, location and phasing of methylated and/or hydroxymethylated cytosines in nucleic acids including long stretches of DNA. In some embodiments, the method may comprise reacting a first portion (aliquot) of a nucleic acid sample with a dioxygenase and optionally a glucosyltransferase in a reaction mixture containing the nucleic acid followed by a reaction with a cytidine deaminase to detect and optionally mapC in a DNA. Optionally, a second portion can be reacted with glucosyltransferase followed by reaction with a cytidine deaminase to detect and optionally mapC in a DNA.

Compositions and methods for analyzing modified nucleotides

A method for identifying any of the presence, location and phasing of modified cytosines (C) in long stretches of nucleic acids is provided. In some embodiments, the method may comprise (a) reacting a first portion of a nucleic acid sample containing at least one C and/or at least one modified C with a DNA glucosyltransferase and a cytidine deaminase to produce a first product and/or reacting a second portion of the sample with a dioxygenase, optionally a DNA glucosyltransferase and a cytidine deaminase to produce a second product and; (b) comparing the sequences from the first and optionally the second product obtained in (a), or amplification products thereof, with each other and/or an untreated reference sequence to determine which Cs in the initial nucleic acid fragment are modified. A modified TET methylcytosine dioxygenase with improved efficiency compared to unmodified TET2 at converting methylcytosine to carboxymethylcytosine is also provided.

A method for identifying the location and phasing of modified cytosines (C) in long stretches of nucleic acids is provided. In some embodiments, the method may comprise (a) reacting a first portion of a nucleic acid sample containing at least one C and/or at least one modified C with a DNA glucosyltransferase and a cytidine deaminase to produce a first product and optionally reacting a second portion of the sample with a dioxygenase and a cytidine deaminase to produce a second product and; (b) comparing the sequences from the first and optionally the second product obtained in (a), or amplification products thereof, with each other and/or an untreated reference sequence to determine which Cs in the initial nucleic acid fragment are modified. A modified TET methylcytosine dioxygenase that is more efficient at converting methylcytosine to carboxymethylcytosine is also provided.

Provided herein in some embodiments is a non-naturally occurring variant of a wild type restriction enzyme defined by SEQ ID NO: 20, wherein the variant has at least a 2 fold increase in cleavage at 5-&#x3b2; glucosylhydroxymethylcytosine (5&#x3b2;ghmC) compared with methylcytosine relative to the wild type enzyme. Methods for examining hydroxymethylation of a DNA sample using the variant enzyme are also provided.

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Gloucester, MA, United States of America

Zhiyi Sun