Spatio-temporal expression of Pbx3 during mouse organogenesis

Area of Science:

• Developmental Biology
• Molecular Genetics
• Genomics

Background:

• Pbx3 is a TALE class homeodomain transcription factor involved in gene regulation.
• Pbx3 is highly expressed in the developing central nervous system (CNS) and is essential for respiration.
• Pbx3-deficient mice exhibit respiratory failure, highlighting its critical role.

Purpose of the Study:

• To characterize Pbx3 expression patterns during organogenesis in non-CNS tissues.
• To understand potential overlapping functions of Pbx3 with other Pbx family members.
• To identify novel roles of Pbx3 in vertebrate development.

Main Methods:

• In situ hybridization on whole mount and sectioned mouse embryos (gestational day E9 to E16.5).
• Analysis of Pbx3 expression across various embryonic tissues and organ systems.

Main Results:

• Early Pbx3 expression (until E12.5) is localized to the embryonic head, forelimbs, and septum transversum.
• Later Pbx3 expression becomes widespread, detected in epithelial, mesenchymal tissues, CNS, and enteric nervous system.
• Pbx3 is specifically expressed in Auerbach's myenteric nerve plexus, proliferating chondrocytes, and early forelimb buds, distinguishing it from Pbx1 and Pbx2.

Conclusions:

• Pbx3 plays diverse roles in organogenesis beyond the CNS, including in the enteric nervous system and cartilage development.
• Pbx3 expression dynamics during chondrogenesis mirror Pbx1, suggesting conserved functions.
• Pbx3 is identified as an early forelimb-specific molecular marker.