Complex genetic and epigenetic regulation deviates gene expression from a unifying global transcriptional program

Area of Science:

• Molecular Biology
• Systems Biology
• Genomics

Background:

• Gene expression changes occur due to environmental or genetic factors.
• Widespread gene expression variations are linked to a global transcriptional program influenced by cellular physiology.
• Eukaryotic regulation is complex, suggesting specific control architectures influencing global programs.

Purpose of the Study:

• To examine the architecture of specific gene regulation controlling global expression programs.
• To develop a framework for analyzing deviations from global transcriptional control.
• To understand the diverse regulatory strategies employed by different gene classes.

Main Methods:

• Utilized Saccharomyces cerevisiae gene expression data under varying nutrient conditions.
• Proposed a five-sector genome partition model integrating resource allocation.
• Analyzed deviations from global control, categorizing genes into invariant, specific, and growth-dependent classes.

Main Results:

• Identified invariant genes dominated by physiology and specific genes departing from it.
• Found that non-invariant gene classes are enriched for regulation by transcription factors (TFs) and epigenetic modulators.
• Observed distinct regulatory strategies, including unique TF actions and diverse chromatin modifier activities.

Conclusions:

• The complex regulatory architecture prevents a single unifying program for genomic-scale expression changes.
• Specific regulatory mechanisms involving TFs and chromatin modifiers modulate the general transcription machinery.
• Understanding these diverse strategies is crucial for comprehending cellular responses to perturbations.