Name: efficient purification and lc-ms/ms-based assay development for ten-eleven translocation-2 5-methylcytosine dioxygenase
Uploaded: 2018-10-15T13:00:00
Description: Watch this Scientific Journal Video about Efficient Purification and LC-MS/MS-based Assay Development for Ten-Eleven Translocation-2 5-Methylcytosine Dioxygenase at JoVE.com

This research was funded by the US Department of Defense in the form of an Idea Award (W81XWH-13-1-0174), Aplastic Anemia &amp; MDS Foundation Grant, and UMRB grant to M.M. Authors thank Mohit Jaiswal and Subhradeep Bhar for initial cloning of TET2 in pDEST14 vector.

1. Cloning and Purification of Untagged Human TET2 Dioxygenase
<ol>
	<li>Clone human TET2 dioxygenase (TET2 1129-1936, &#916;1481-1843) into the pDEST14 destination vector using the site-specific recombination technique as previously described22. 
	NOTE: Previous studies have demonstrated that the C-terminal TET2 dioxygenase (TET2 1129-1936, &#916;1481-1843) domain is the minimal catalytically active domain21,23. In order to express...

<ol>
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Mutations in TET2 gene are some of the most frequently detected genetic changes in patients with diverse hematopoietic malignancies. To date hundreds of different TET2 mutations, which include nonsense, frame-shift, and missense mutations, have been identified in patients12. Patients with TET2 mutations show low levels of genomic 5hmC in the bone marrow compared to those with wt-TET214. Mutant TET2 knock-in experiments have recapitulated the effects of the...

The C5 position of cytosine bases within CpG dinucleotides is the predominant methylation site (5mCpG) in mammalian genomes1. In addition, a number of recent studies have uncovered extensive C5 cytosine methylation (5mC) in non-CpG sites (5mCpH, where H = A, T, or C)2,3. 5mC modification serves as a transcriptional silencer at endogenous retrotransposons and gene promoters3,4,5. DNA methylation at 5mC also plays important roles in X chromosome inactivation, gene imprinting, nuclear reprogramming and tissue-specific gene expression5,6,7. Methylation of cytosine at the C5 position is carried out by DNA methyltransferases, and mutations in these enzymes cause significant developmental defects8. The removal of 5mC marks are initiated by TET1-3 5mC oxidases9,10. These TET-family dioxygenases convert 5mC into 5-hydroxymethylcytosine (5hmC), 5-formylcytosine (5fC) and 5-carboxylcytosine (5caC) by sequential oxidation steps11,12,13. Finally, thymine-DNA glycosylase replaces 5fC or 5caC to unmodified cytosine using the base excision repair pathway11.
The human TET2 gene was identified as a frequently mutated gene in diverse hematopoietic malignancies including myelodysplastic syndromes (MDS)14,15,16, MDS-myeloproliferative neoplasms (MDS-MPN), and acute myeloid leukemia (AML) originating from MDS and MDS-MPN16. The levels of 5hmC modification in the bone marrow DNA are lower in patients with TET2 mutations compared to those with wild type (wt)-TET214. A number of groups have developed TET2-knockout mouse models to elucidate its role in normal hematopoiesis and myeloid transformation17,18,19,20. These mice with mutations in the TET2 gene were initially normal and viable, but manifested diverse hematopoietic malignancies as they aged causing their early death. These studies showed the important roles played by the wt-TET2 in normal hematopoietic differentiation. In these mouse models, the heterozygous hematopoietic stem cells (TET2+/- HSCs) and homozygous TET2-/-&#160;HSCs had a competitive advantage over homozygous wt-TET2 HSCs in repopulating hematopoietic lineages as both TET2+/- and TET2-/-&#160;HSCs developed diverse hematopoietic malignancies17,18. These studies demonstrate that haploinsufficiency of TET2 dioxygenase alters the development of HSCs and results in hematopoietic malignancies.
Similar to mice with mutations in the TET2 gene, most leukemia patients manifest haploinsufficiency of TET2 dioxygenase activity. These mostly heterozygous somatic mutations include frame-shift and nonsense mutations dispersed throughout the TET2 gene body while missense mutations that are most clustered in the dioxygenase domain12. To date, little characterization of wt- and mutant-TET2 is reported in the literature mainly due to difficulties with the production of TET2 dioxygenase and its assay21. Here, we report a simple single-step purification of native TET2 dioxygenase using ion exchange chromatography. Further, a quantitative LC-MS/MS assay was optimized and used to measure the enzymatic activity of native TET2 dioxygenase.

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			<td height="21" style="height:21px;width:252px;">HEPES</td>
			<td style="width:201px;">Carbosynth</td>
			<td style="width:119px;">FH31182</td>
			<td style="width:167px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:252px;">Iron(II) sulfate heptahydrate</td>
			<td>Sigma-Aldrich</td>
			<td>F8633</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:252px;">&#945;-Ketoglutaric acid (2-Oxoglutaric acid)</td>
			<td>Sigma-Aldrich</td>
			<td>K1750</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:252px;">L-Ascorbic acid</td>
			<td>Sigma-Aldrich</td>
			<td>A4544</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:252px;">Ethylenediaminetetraacetic acid disodium salt dihydrate</td>
			<td style="width:201px;">Sigma-Aldrich</td>
			<td>E5134</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:252px;">Ammonium acetate</td>
			<td>Sigma-Aldrich</td>
			<td>A1542</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:252px;">Acetonitrile</td>
			<td>Fisher Scientific</td>
			<td>75-05-8</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:252px;">HPLC grade water</td>
			<td>Fisher Scientific</td>
			<td>7732-18-5</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:252px;">Oligo clean and concentrator</td>
			<td>Zymo Research</td>
			<td>D4061</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:252px;">DNAse I</td>
			<td>New England Biolabs</td>
			<td>M0303S</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:252px;">S1 Nuclease</td>
			<td>Thermo Scientific</td>
			<td>ENO321</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:252px;">CIAP (Calf intestinal alkaline phosphatase)</td>
			<td>New England Biolabs</td>
			<td>M0290S</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:252px;">LB Media</td>
			<td>Affymetrix</td>
			<td>J75852</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:252px;">IPTG</td>
			<td>Carbosynth</td>
			<td>EI05931</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:252px;">MES [2-(N-Morpholino)ethanesulfonic acid monohydrate]</td>
			<td style="width:201px;">Carbosynth</td>
			<td>FM37015</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:252px;">Sodium chloride</td>
			<td>Fisher Scientific</td>
			<td>7647-14-5</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:252px;">Glycerol</td>
			<td>Sigma-Aldrich</td>
			<td>G7893</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:252px;">SP Sepharose</td>
			<td>Fisher Scientific</td>
			<td>45-002-934</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:252px;">2&#39;-Deoxy-5-methylcytidine</td>
			<td>TCI</td>
			<td>D3610</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:252px;">2&#39;-Deoxy-5-hydroxymethyalcytidine</td>
			<td>TCI</td>
			<td>D4220</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:252px;">2&#39;-Deoxycytidine-5-carboxylic acid, sodium salt</td>
			<td>Berry &#38; Associates</td>
			<td>PY 7593</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:252px;">5-Formyl-2&#39;-deoxycytidine</td>
			<td>Berry &#38; Associates</td>
			<td>PY 7589</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:252px;">2&#39;-Deoxycytidine</td>
			<td>Berry &#38; Associates</td>
			<td>PY 7216</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:252px;">2&#39;-Deoxyadenosine</td>
			<td>Carbosynth</td>
			<td>ND04011</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:252px;">2&#39;-Deoxyguanosine</td>
			<td>Carbosynth</td>
			<td>ND06306</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:252px;">2&#39;-Deoxythymidine</td>
			<td>VWR Life Science</td>
			<td>97061-764</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:252px;">Gateway technology</td>
			<td style="width:201px;">Thermo Fisher</td>
			<td style="width:119px;">11801016</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:252px;">Beckman Allegra X-15R centrifuge&#160;</td>
			<td style="width:201px;">Beckman Coulter</td>
			<td style="width:119px;">392932</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:252px;">Sonic Dismembrator 550</td>
			<td style="width:201px;">Fisher Scientific</td>
			<td style="width:119px;">XL2020</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:252px;">&#196;KTA FPLC system</td>
			<td style="width:201px;">Pharmacia (GE Healthcare)</td>
			<td style="width:119px;">18116468</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:252px;">FreeZone 4.5 freeze dry system</td>
			<td style="width:201px;">Labconco</td>
			<td style="width:119px;">7750020</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:252px;">Zymo Oligo purification columns&#160;</td>
			<td style="width:201px;">Zymo Research</td>
			<td style="width:119px;">D4061</td>
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			<td height="21" style="height:21px;width:252px;">BDS Hypersil C18 column</td>
			<td style="width:201px;">Keystone Scientific, INC</td>
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efficient purification and lc-ms/ms-based assay development for ten-eleven translocation-2 5-methylcytosine dioxygenase

The epigenetic transcription regulation mediated by 5-methylcytosine (5mC) has played a critical role in eukaryotic development. Demethylation of these epigenetic marks is accomplished by sequential oxidation by ten-eleven translocation dioxygenases (TET1-3), followed by the thymine-DNA glycosylase-dependent base excision repair. Inactivation of the TET2 gene due to genetic mutations or by other epigenetic mechanisms is associated with a poor prognosis in patients with diverse cancers, especially hematopoietic malignancies. Here, we describe an efficient single step purification of enzymatically active untagged human TET2 dioxygenase using cation exchange chromatography. We further provide a liquid chromatography-tandem mass spectrometry (LC-MS/MS) approach that can separate and quantify the four normal DNA bases (A, T, G, and C), as well as the four modified cytosine bases (5-methyl, 5-hydroxymethyl, 5-formyl, and 5-carboxyl). This assay can be used to evaluate the activity of wild type and mutant TET2 dioxygenases.

Dynamic modification of 5mC in DNA by TET-family dioxygenases plays important roles in epigenetic transcriptional regulations. TET2 dioxygenase is frequently mutated in diverse hematopoietic malignancies12. To investigate the role of the TET2 enzyme in normal development and disease, we have cloned its minimal catalytically active domain without any affinity tag into the pDEST14 vector22. The untagged TET2 dioxygenase was produced at &#8764;...

Watch this Scientific Journal Video about Efficient Purification and LC-MS/MS-based Assay Development for Ten-Eleven Translocation-2 5-Methylcytosine Dioxygenase at JoVE.com

Efficient Purification and LC-MS/MS-based Assay Development for Ten-Eleven Translocation-2 5-Methylcytosine Dioxygenase

Here, we present a protocol for an efficient single step purification of the active untagged human ten-eleven translocation-2 (TET2) 5-methylcytosine dioxygenase using ion-exchange chromatography and its assay using a liquid chromatography-tandem mass spectrometry (LC-MS/MS)-based approach.

The epigenetic transcription regulation mediated by 5-methylcytosine (5mC) has played a critical role in eukaryotic development. Demethylation of these ...

Research

JoVE Journal

Biochemistry

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