Evaluating the global CpG methylation status of native DNA utilizing a bipartite split-luciferase sensor

Area of Science:

• Epigenetics
• Molecular Biology
• Cancer Research

Background:

• Epigenetic modifications, including DNA methylation, regulate gene expression and cell fate.
• CpG methylation (mCpG) is linked to cancer when it occurs at tumor suppressor gene promoters.
• Current methods for assessing global DNA methylation can be time-consuming and complex.

Purpose of the Study:

• To develop a rapid, direct method for assessing global DNA methylation levels.
• To identify specific domains that can selectively bind methylated CpG sites.
• To create a methylation-dependent sensor for real-time DNA methylation detection.

Main Methods:

• Screening of methyl-CpG binding domains (MBDs), Kaiso, and SET- and RING-associated domains using split-luciferase.
• Identification and utilization of the MBD1 domain for its high selectivity.
• Construction of a bipartite sensor by linking MBD1 domains to split-luciferase halves.
• Validation of the sensor using in vitro genomic DNA and HeLa cell DNA treated with a methyltransferase inhibitor.

Main Results:

• MBD1 demonstrated over 90-fold selectivity in discriminating between mCpG and CpG sites.
• A novel bipartite sensor was successfully constructed, enabling methylation-dependent luciferase reassembly.
• The sensor accurately determined global DNA methylation levels in vitro without prior DNA treatment.
• The sensor effectively monitored dose-dependent methylation changes in response to 5-aza-2'-deoxycytidine.

Conclusions:

• The developed bipartite sensor provides a rapid and direct method for assessing global DNA methylation.
• MBD1 is a highly selective domain for detecting methylated CpG sites.
• This technology has potential applications in cancer research and epigenetic studies.