Tissue-specific enhancer repression through molecular integration of cell signaling inputs

Area of Science:

• Developmental Biology
• Genetics
• Molecular Biology

Background:

• Drosophila leg development involves complex genetic cascades and transcription factors.
• The precise cross-regulatory interactions refining leg patterning are not fully understood at the gene expression level.

Purpose of the Study:

• To investigate the roles of C15 and Bowl transcription factors in regulating the bric-à-brac2 (bab2) gene during Drosophila leg development.
• To elucidate the molecular mechanisms by which C15 and Bowl interact with the leg/antennal enhancer (LAE) and influence gene expression.

Main Methods:

• Genetic analysis in Drosophila.
• Molecular analyses including enhancer-reporter assays and protein-DNA interaction studies.
• Investigation of protein-protein interactions.

Main Results:

• C15 and Bowl transcription factors directly interact with the LAE enhancer, acting as a repressive duo.
• The appendage patterning gene bab2 is a direct target of the Bowl repressor.
• C15 interacts with the Distal-less (Dll) activator competitively binding to the LAE enhancer.
• C15 and Bowl also regulate the expression of the Rotund (Rn) gene.

Conclusions:

• The study identifies C15 and Bowl as key repressors in Drosophila leg patterning, directly regulating bab2 and rn expression.
• These repressors, responding to cell signaling, refine gene expression along the limb proximo-distal axis through competitive binding and interaction with activators like Dll.