DeltaC and DeltaD ligands play different roles in the segmentation clock dynamics

Area of Science:

• Developmental biology
• Molecular biology
• Genetics

Background:

• The vertebrate segmentation clock, involving Her1 and Her7 proteins, drives embryonic somite segmentation.
• Notch signaling, activated by DeltaC and DeltaD ligands, regulates clock gene transcription.

Purpose of the Study:

• To investigate the roles of DeltaC and DeltaD proteins in regulating her1 and her7 gene transcription.
• To explore the functionality of DeltaC and DeltaD homo- and heterodimers in the segmentation clock.

Main Methods:

• Single molecule fluorescent in situ hybridization (smFISH) was used to count transcripts.
• Experiments were conducted in various genetic backgrounds of zebrafish embryos.
• A computational model was employed to analyze clock dynamics.

Main Results:

• DeltaD homodimers were found to be functional in regulating clock gene transcription.
• Notch signaling was shown to promote transcription of both deltaC and deltaD genes, forming a positive feedback loop.
• Differential roles of DeltaC and DeltaD dimers in clock synchronization and transcript numbers were identified.

Conclusions:

• DeltaD homodimers contribute to the zebrafish segmentation clock mechanism.
• A novel positive feedback loop involving Notch signaling in deltaC and deltaD gene regulation was discovered.
• Understanding this pathway provides insights into robust somite segmentation and inspires further research.