Armadillo/Pangolin regulates PCNA and DREF promoter activities

Area of Science:

• Molecular Biology
• Genetics
• Cell Signaling

Background:

• The Wingless (Wg) signaling pathway is crucial for development and cellular processes.
• Armadillo and Pangolin (dTCF) are key downstream effectors of the Wg pathway.
• Understanding the transcriptional targets of Wg signaling is essential for deciphering developmental regulation.

Purpose of the Study:

• To identify and characterize the direct transcriptional targets of the Armadillo/Pangolin complex.
• To investigate the role of Drosophila CREB-binding protein (dCBP) in modulating Wg-mediated gene activation.
• To elucidate the gene-specific regulatory mechanisms of Wg signaling in DNA replication.

Main Methods:

• Transient luciferase expression assays to measure gene transcription.
• Band mobility shift assays to confirm direct DNA-protein interactions.
• GAL4-UAS system in adult female Drosophila to validate gene stimulation in vivo.

Main Results:

• Armadillo/Pangolin directly activates transcription of the Drosophila proliferating cell nuclear antigen (PCNA) and DNA replication-related element-binding factor (DREF) genes.
• PCNA was confirmed as a direct target of the Armadillo/Pangolin complex.
• dCBP potentiated Armadillo-mediated activation of PCNA, contrary to expectations, and modulated DREF activation differently.

Conclusions:

• PCNA and DREF are direct transcriptional targets of the Armadillo/Pangolin complex, linking Wg signaling to DNA replication.
• dCBP exhibits gene-specific modulation of Wg signaling, impacting PCNA and DREF activation distinctively.
• These findings reveal a nuanced regulatory role for dCBP in Wg pathway output.