Chromatin states modify network motifs contributing to cell-specific functions.

Area of Science:

• Genomics
• Epigenetics
• Systems Biology

Background:

• Epigenetic modifications regulate crucial biological processes like cell proliferation and apoptosis by altering chromatin conformation and gene expression.
• Network motifs, recurring patterns in biological networks, play significant roles in cellular regulation.

Purpose of the Study:

• To investigate the association between chromatin states and network motifs in gene regulatory networks.
• To understand how chromatin states influence the function and cell-specificity of network motifs, especially feedforward loops (FFLs).

Main Methods:

• Assembled chromatin state-modified regulatory networks using 269 ChIP-seq datasets and chromatin state data from four cell types.
• Analyzed the association between various chromatin states and network motifs, with a focus on FFLs.
• Compared FFLs in cancerous/stem and primary cell lines to identify alterations.

Main Results:

• Found significant associations between chromatin states and network motifs, particularly FFLs.
• Demonstrated that distinct chromatin state compositions within FFLs affect target gene expression levels and translational control.
• Revealed that chromatin state-modified FFLs are highly cell-specific and dictate cell-selective functions, exemplified by embryonic stem cell-specific FFLs involved in developmental gene regulation.
• Identified specific chromatin state alterations in cancerous/stem cells compared to primary cells that, along with motif structural changes, contribute to functional differences.

Conclusions:

• Dynamic epigenetic modifications are crucial for network motifs to control cell-specific functions.
• Chromatin state-modified FFLs are key determinants of cell identity and function.
• Identifying specific chromatin alterations in FFLs can aid in prioritizing candidate genes for further study and understanding cell-to-cell functional divergence.