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

Area of Science:

• Epigenetics
• Molecular Biology
• Biochemistry

Background:

• 5-methylcytosine (5mC) epigenetic marks are vital for eukaryotic development and gene regulation.
• Ten-eleven translocation (TET) dioxygenases mediate DNA demethylation through sequential oxidation, followed by base excision repair.
• TET2 gene inactivation is linked to poor prognosis in various cancers, particularly hematopoietic malignancies.

Purpose of the Study:

• To develop an efficient method for purifying enzymatically active, untagged human TET2.
• To establish a quantitative assay for measuring TET2 dioxygenase activity.
• To enable the evaluation of both wild-type and mutant TET2 enzyme function.

Main Methods:

• Single-step purification of untagged human TET2 using cation exchange chromatography.
• Development of a liquid chromatography-tandem mass spectrometry (LC-MS/MS) assay.
• Quantification of normal DNA bases (A, T, G, C) and modified cytosine bases (5mC, 5hmC, 5fC, 5caC).

Main Results:

• An efficient protocol for obtaining enzymatically active, untagged human TET2 was established.
• A robust LC-MS/MS assay capable of separating and quantifying four normal DNA bases and four modified cytosine bases was developed.
• The assay successfully differentiates and quantifies various DNA base modifications relevant to TET2 activity.

Conclusions:

• The described purification method yields active TET2 enzyme suitable for biochemical studies.
• The LC-MS/MS assay provides a sensitive tool for assessing TET2 dioxygenase activity.
• These advancements facilitate research into TET2 function, mutations, and their role in cancer.