Epigenetic modifications affect Dnmt3L expression

Area of Science:

• Epigenetics
• Gene Regulation
• Molecular Biology

Background:

• Imprinted genes are expressed from one allele due to differential DNA methylation.
• DNA cytosine-5-methyltransferase 3 like (Dnmt3L) is crucial for maternal imprinting.
• Dnmt3L is a de novo methyltransferase regulating imprinting.

Purpose of the Study:

• Characterize the promoter region of the mouse Dnmt3L gene.
• Investigate the role of DNA methylation and transcription factors in Dnmt3L regulation.
• Determine the epigenetic control mechanisms governing Dnmt3L expression.

Main Methods:

• Transient transfection assays with 5'-deletion promoter constructs.
• Electrophoretic mobility-shift assays and mutation analysis for transcription factor binding.
• In vitro methylation, bisulphite sequencing, and quantitative reverse transcriptase-PCR.
• Treatment with deacetylase and methyltransferase inhibitors.

Main Results:

• A minimal promoter region of 440 bp upstream of the start site was identified.
• Four functional binding sites for Sp1 and Sp3 transcription factors were found in the minimal promoter.
• In vitro methylation significantly decreased Dnmt3L promoter activity.
• CpG sites were unmethylated in highly expressing cells (testis, ESCs) and methylated in low/non-expressing cells.
• Inhibitors (trichostatin A, 5-aza-2'-deoxycytidine) induced Dnmt3L mRNA expression.

Conclusions:

• Dnmt3L gene expression is regulated by epigenetic mechanisms, including DNA methylation.
• Sp1/Sp3 transcription factors play a role in regulating Dnmt3L.
• CpG methylation status correlates with Dnmt3L expression levels across different tissues and cell lines.
• Epigenetic modifications are key to controlling Dnmt3L gene regulation.