Hindbrain patterning: FGFs regulate Krox20 and mafB/kr expression in the otic/preotic region

Area of Science:

• Developmental biology
• Molecular genetics
• Neuroscience

Background:

• Krox20 and mafB/kr are key regulatory genes in hindbrain segmentation and anteroposterior patterning.
• These genes are expressed in specific rhombomeres and neural crest cells within the developing hindbrain.

Purpose of the Study:

• To investigate the role of fibroblast growth factors (FGFs) in regulating Krox20 and mafB/kr gene expression during hindbrain development.

Main Methods:

• Application of exogenous FGFs to chick embryos (4-7 somites).
• Inhibition of FGF signaling pathways in chick embryos.
• Analysis of Krox20 and mafB/kr gene expression patterns in the hindbrain neuroepithelium and neural crest.

Main Results:

• Exogenous FGFs induced ectopic expression of Krox20 and mafB/kr in the hindbrain neural crest (r7, r8) and expanded their expression domains in the neuroepithelium.
• Inhibition of FGF signaling caused significant downregulation of Krox20 and mafB/kr in both hindbrain neuroepithelium and neural crest.

Conclusions:

• FGF signaling plays a critical role in the regional induction and maintenance of Krox20 and mafB/kr expression.
• FGFs have a novel function in regulating hindbrain segmentation and AP patterning, beyond their general role in neural development.