Uncoupling histone modification crosstalk by engineering lysine demethylase LSD1.

Area of Science:

• Epigenetics
• Molecular Biology
• Biochemistry

Background:

• Biochemical crosstalk between histone modifications is common in epigenetic regulation.
• Lysine-specific demethylase 1 (LSD1) activity is inhibited by histone H3 Lysine 14 acetylation.
• The functional significance of this crosstalk in cellular processes remains unclear.

Purpose of the Study:

• To investigate the functional consequences of disconnecting histone modification crosstalk for LSD1.
• To engineer a mutant LSD1 enzyme resistant to inhibition by H3 Lys14 acetylation.
• To analyze the impact of this engineered enzyme on gene expression and chromatin states.

Main Methods:

• Engineered a Y391K mutant form of LSD1, insensitive to H3 Lys14 acetylation.
• Utilized CRISPR technology to knock in the Y391K LSD1 mutant into K562 cells.
• Performed chromatin profiling to assess histone modifications and gene expression changes.

Main Results:

• K562 cells with Y391K LSD1 showed decreased expression of genes involved in cellular adhesion and myeloid leukocyte activation.
• Silenced genes' regulatory regions exhibited high H3 Lys14 acetylation.
• Edited cells displayed reduced H3 mono-methyl Lys4 near silenced genes, indicating enhanced LSD1 demethylase activity.

Conclusions:

• Disconnecting histone modification crosstalk for LSD1 impacts gene expression, specifically silencing genes related to cellular adhesion and myeloid leukocyte activation.
• This study provides functional insights into the role of H3 Lys14 acetylation in regulating LSD1 activity and downstream gene expression.
• The engineered LSD1 mutant serves as a valuable tool for dissecting epigenetic crosstalk mechanisms.