Developmental expression of chick twist and its regulation during limb patterning

Area of Science:

• Developmental Biology
• Molecular Biology
• Genetics

Background:

• The Twist gene family plays a vital role in embryonic development across various species.
• Understanding the specific functions and regulation of Twist genes is essential for comprehending developmental processes.

Purpose of the Study:

• To isolate and characterize the chick Twist gene (cTwist).
• To investigate the expression pattern of cTwist during chick embryonic development.
• To explore the regulatory mechanisms controlling cTwist expression, particularly in limb mesenchyme.

Main Methods:

• Whole mount in situ hybridization was employed to visualize cTwist transcript distribution.
• Expression patterns were analyzed in various embryonic tissues, including somites, mesoderm, limb buds, branchial arches, and developing feathers.
• The influence of signaling molecules like FGFs, RA, and SHH on cTwist expression was examined.

Main Results:

• cTwist transcripts were detected in multiple developing embryonic structures, including somites, lateral plate mesoderm, limb mesenchyme, branchial arches, and head mesenchyme.
• Later expression was observed in sclerotome, dermatome, limb bud mesenchyme, interdigital regions, and distal processes of the maxillary and mandibular.
• cTwist expression in limb mesenchyme is regulated by the apical ectodermal ridge (AER), FGFs, RA, and SHH, with FGFs and AER playing a critical role.

Conclusions:

• The study successfully isolated and characterized the chick Twist gene (cTwist).
• cTwist exhibits a dynamic expression pattern throughout chick embryogenesis, highlighting its involvement in diverse developmental processes.
• Evidence suggests a significant interplay between cTwist and FGF signaling pathways in regulating limb development.