The role of inner nuclear membrane protein emerin in myogenesis

Figures

• 

  FIGURE 1. The myogenic differentiation program. Upon injury, quiescent satellites divide asymmetrically with one cell (Myf5−) replenishing the stem cell niche, while the other cell (Myf5+) becomes an activated satellite cell. Activated satellite cells continue differentiating to become committed myoblasts and begin expressing MyoD, while downregulating Pax7 expression. Myoblasts then exit the cell cycle to form myocytes, which begin expressing myogenin. Myocytes will then align and fuse into myotubes. Myotubes then mature and become integrated into myofibers.

• 

  FIGURE 2. Lamina‐associated domains (LADs). Chromatin organized at the nuclear lamina are termed LADs. LADs at the nuclear envelope are enriched for the repressive histone modifications H3K9me2/3 and H3K27me3 (red). Non‐LAD regions are shown (green) and possess transcriptionally active epigenetic marks, notably H3K9ac and H4K5ac. Figure created with BioRender.com.

• 

  FIGURE 3. Emerin interacts with histone modification machinery. Emerin (green) binds to HDAC3 (red) and activates its catalytic activity to remove acetylation on H4K5 to repress chromatin. Emerin interacts with the PRC2 complex (orange) and G9a (turquoise) which deposits methylation marks on H3K27 and H3K9, respectively. These methylation marks result in further compaction of the chromatin. Emerin and BAF (purple) may also help to organize chromatin at the nuclear envelope. Figure created with BioRender.com.

• 

  FIGURE 4. Emerin binds transcription regulators at the nuclear envelope. Emerin modulates transcription of Notch target genes by restricting NICD (maroon) to the nuclear envelope with BAF (aqua). Emerin prevents nuclear accumulation of β‐catenin (yellow) to prevent transcription of Wnt target genes. Emerin binds to GCL (green) and indirectly sequesters DP/E2F at the NE to prevent transcription of E2F target genes. Emerin binds Btf (pink) to prevent transcriptional repression of anti‐apoptotic genes. Emerin binds to Lmo7 (blue) to prevent transcription of Lmo7 target genes, including MyoD1 and Pax3. Figure created with BioRender.com.