Modulation of Dnmt3b function in vitro by interactions with Dnmt3L, Dnmt3a and Dnmt3b splice variants

Area of Science:

• Epigenetics
• Molecular Biology
• Genetics

Background:

• DNA methylation is crucial for gene regulation, established by DNA methyltransferases (DNMTs).
• DNMT3B dysfunction is implicated in cancer and genetic disorders.
• DNMT3B undergoes alternative splicing, but its functional impact is poorly understood.

Purpose of the Study:

• To investigate the effects of DNMT3B alternative splicing and mutations on its DNA binding, self-interaction, and methylation activity.
• To explore the role of DNMT3B's N-terminal region, including the PWWP domain.
• To determine if inactive DNMT3B isoforms can modulate DNMT3A-DNMT3L complex activity.

Main Methods:

• In vitro assays to assess DNMT3B function.
• Analysis of DNA binding, protein-protein interactions, and catalytic activity.
• Examination of cellular localization and the impact of splicing/mutations.

Main Results:

• The C-terminal catalytic domain is essential, but the N-terminal region, including the PWWP domain, also plays a significant role in DNMT3B function.
• Alternative splicing and domain deletions affect DNMT3B localization and activity.
• Extensive DNMT3B self-interactions modulate its activity, and inactive DNMT3B isoforms can regulate DNMT3A-DNMT3L complexes.

Conclusions:

• DNMT3B splicing and mutations significantly impact its function, localization, and interactions.
• Inactive DNMT3B isoforms may play a regulatory role in vivo, influencing genomic methylation.
• These findings provide new insights into DNMT3B's complex role in epigenetic regulation and disease.