Expression and function of transcription factor cMyb during cranial neural crest development

Area of Science:

• Developmental Biology
• Molecular Biology
• Genetics

Background:

• The transcription factor cMyb is known for its role in vertebrate hematopoiesis.
• Its function and distribution during early embryonic development were largely unknown.
• Understanding cMyb's role in early development is critical for comprehending developmental processes.

Purpose of the Study:

• To investigate the expression pattern of cMyb during early chick embryogenesis.
• To determine the function of cMyb in the development of cranial neural crest cells.
• To elucidate the hierarchical position of cMyb within the cranial neural crest gene regulatory network.

Main Methods:

• Analysis of cMyb transcript localization in gastrulating and neurulating chick embryos.
• Morpholino-mediated knockdown of cMyb to assess its functional impact.
• Quantitative analysis of key developmental and neural crest specifier gene expression (Pax7, Twist, Slug/Snail2, Ets1, Zic1, FoxD3, Sox9) following cMyb knockdown.

Main Results:

• cMyb transcripts were detected in the neural plate during gastrulation and subsequently in cranial neural folds and migrating cranial neural crest cells.
• Knockdown of cMyb led to reduced expression of Pax7, Twist, and Slug/Snail2, and complete elimination of Ets1 expression.
• Loss of cMyb resulted in abnormal maintenance of Zic1 expression, with minimal effects on FoxD3 and Sox9.

Conclusions:

• cMyb plays a significant role in the early development of cranial neural crest cells in chick embryos.
• cMyb is positioned hierarchically within the cranial neural crest gene regulatory network.
• cMyb likely directly inhibits Zic1 and acts upstream of Ets1 and a subset of neural crest specifier genes.