Podocin-Green Fluorescence Protein Allows Visualization and Functional Analysis of Podocytes

• Published in: Journal of the American Society of Nephrology Vol. 22; no. 6; pp. 1019 - 1023
• Main Authors: BING HE, EBARASI, Lwaki, HULTENBY, Kjell, TRYGGVASON, Karl, BETSHOLTZ, Christer
• Format: Journal Article
• Language: English
• Published: Washington, DC American Society of Nephrology 01.06.2011
• Subjects: Animals; Animals, Genetically Modified; Biological and medical sciences; Brief Communications; Green Fluorescent Proteins - genetics; Green Fluorescent Proteins - metabolism; Intracellular Signaling Peptides and Proteins - genetics; Intracellular Signaling Peptides and Proteins - metabolism; Kidney Glomerulus - cytology; Kidney Glomerulus - metabolism; Kidney Glomerulus - ultrastructure; Medical sciences; Medicin och hälsovetenskap; Membrane Proteins - genetics; Membrane Proteins - metabolism; Microscopy, Electron, Scanning; Models, Animal; Nephrology. Urinary tract diseases; Podocytes - cytology; Podocytes - metabolism; Podocytes - ultrastructure; Zebrafish; Zebrafish Proteins - genetics; Zebrafish Proteins - metabolism; Renal glomerulus; Podocyte; Nephrology; Urinary system; Green fluorescent protein; Functional analysis; Kidney; Urology; Podocin
• ISSN: 1046-6673; 1533-3450; 1533-3450
• DOI: 10.1681/ASN.2010121291

Podocytes do not remain fully differentiated when cultured, and they are difficult to image in vivo, making the study of podocyte biology challenging. Zebrafish embryos are transparent and develop a single, midline, pronephric glomerulus accessible for imaging and systematic functional analysis. Here, we describe a transgenic zebrafish line that expresses green fluorescence protein (GFP) from the zebrafish podocin promoter. The line recapitulates the endogenous pronephric podocin expression pattern, showing GFP expression exclusively in podocytes starting 2 days postfertilization. Using the podocyte GFP signal as a guide for dissection, we examined the pronephric glomerulus by scanning electron microscopy; the surface ultrastructure exhibited fine, interdigitating podocyte foot processes surrounding glomerular capillaries. To determine whether the GFP signal could serve as a direct readout of developmental abnormalities or injury to the glomerulus, we knocked down the podocyte-associated protein crb2b; this led to a loss of GFP signal. Thus, podocin-GFP zebrafish provide a model for ultrastructural studies and in vivo visualization and functional analysis of glomerular podocytes. This model should also be useful for high-throughput genetic or chemical analysis of glomerular development and function.