Expression of E93 provides an instructive cue to control dynamic enhancer activity and chromatin accessibility during...

Area of Science:

• Developmental biology
• Molecular biology
• Genetics

Background:

• Understanding how temporal cues integrate with spatial information to regulate gene expression during development is crucial.
• The role of transcription factors in mediating developmental timing is an active area of research.

Purpose of the Study:

• To investigate the hypothesis that the *Drosophila* transcription factor E93 controls temporal gene expression by modulating chromatin accessibility.
• To determine if E93 expression can alter enhancer activity and mimic later developmental patterns.

Main Methods:

• Utilizing precocious expression of E93 in *Drosophila* wing development.
• Employing genomic profiling to assess changes in chromatin accessibility at target enhancers.
• Analyzing enhancer activity patterns in response to E93 manipulation.

Main Results:

• Precocious E93 expression simultaneously activated and deactivated target enhancers, with patterns resembling later wild-type development.
• E93 directly regulated chromatin accessibility at a subset of its target genes, accelerating the developmental program.
• Enhancers unresponsive to early E93 became responsive after a developmental transition, indicating parallel temporal pathways.

Conclusions:

• E93 acts as an instructive cue, establishing a developmental time window through chromatin accessibility control.
• Developmental timing involves E93-mediated chromatin modifications and parallel temporal pathways.
• This study provides insights into the molecular mechanisms governing developmental progression.