DOT1L-mediated H3K79me2 directs B-cell repertoire establishment, marginal zone development, and germinal center...

Area of Science:

• Epigenetics
• Immunology
• Molecular Biology

Background:

• Disruptor of telomeric silencing 1-like (DOT1L) is an epigenetic regulator involved in gene expression via histone methylation.
• DOT1L is implicated as an oncogenic driver in lymphoid cancers, but its precise role in B-cell maturation is unclear.

Purpose of the Study:

• To elucidate the gene targets of H3K79me2 and the mechanistic role of DOT1L in murine B-cell development.
• To understand how DOT1L activity influences B-cell maturation, marginal zone (MZ) B-cell generation, and germinal center (GC) B-cell biology.

Main Methods:

• Deep-sequencing to identify H3K79me2 genomic distribution.
• Conditional knockout mouse models to study DOT1L function during B-cell development.

Main Results:

• DOT1L is upregulated in pro B cells and H3K79me2 accumulates during B-cell maturation.
• DOT1L is essential for pre-B cell expansion and B-cell receptor repertoire diversity.
• DOT1L deficiency leads to attenuated MZ B cells and impaired GC B-cell differentiation.

Conclusions:

• DOT1L plays a vital role in B-cell lymphopoiesis, MZ B-cell generation, and GC B-cell biology.
• DOT1L regulates transcription and cell cycle across various B-cell development stages.
• H3K79me2 deposition by DOT1L is critical for establishing MZ and GC B-cell gene expression programs.