Evolution of gene expression patterns in a model of branching morphogenesis

Area of Science:

• Developmental Biology
• Molecular Biology
• Genomics

Background:

• Branching morphogenesis of the ureteric bud is crucial for forming the kidney's collecting system.
• A cell culture model using ureteric bud (UB) cells stimulated with metanephric mesenchymal conditioned media (BSN-CM) mimics this process.
• Understanding the gene regulation underlying this morphogenesis is essential.

Purpose of the Study:

• To investigate the gene expression patterns during kidney collecting system branching morphogenesis.
• To identify key genes and pathways involved in ureteric bud development using a cell culture model.

Main Methods:

• Utilized high-density cDNA arrays to analyze gene expression in UB cells stimulated with BSN-CM.
• Developed computational methods, including "vector analysis," for gene quantification and clustering based on differential expression.
• Surveyed expression of epithelial markers and secreted factors in both UB and BSN cells.

Main Results:

• Identified differential expression of transcription factors known to regulate morphogenesis.
• Observed downregulation of pro-apoptotic genes and upregulation of anti-apoptotic genes.
• Found upregulation of secreted factors, including growth factors, cytokines, and extracellular proteinases.
• Correlated specific cellular morphologies with distinct genomic expression subsets.

Conclusions:

• The study provides insights into the molecular mechanisms governing kidney collecting system development.
• Gene expression changes support a general model for epithelial branching morphogenesis.
• Distinct morphogenetic mechanisms may operate at different stages of tubule evolution.