Targeted Inactivation of EGF Receptor Inhibits Renal Collecting Duct Development and Function

• Published in: Journal of the American Society of Nephrology Vol. 21; no. 4; pp. 573 - 578
• Main Authors: ZHAO ZHANG, PASCUET, Elena, HUEBER, Pierre-Alain, CHU, Leelee, BICHET, Daniel G, LEE, Tang-Cheng, THREADGILL, David W, GOODYER, Paul
• Format: Journal Article
• Language: English
• Published: Washington, DC American Society of Nephrology 01-04-2010
• Subjects: Animals; Biological and medical sciences; Brief Communication; Gene Expression Regulation, Developmental; Gene Silencing; Kidney Tubules, Collecting - embryology; Medical sciences; Mice; Mice, Knockout; Nephrology. Urinary tract diseases; Receptor, Epidermal Growth Factor - physiology; Nephrology; Renal function; Urinary system; Targeting; Development; Inhibitor; Collecting duct; Inactivation; Kidney; Epidermal growth factor receptor; Urology
• ISSN: 1046-6673; 1533-3450
• DOI: 10.1681/asn.2009070719

The ureteric bud (UB) expresses high levels of the EGF receptor (EGFR) during kidney development, but its function in this setting is unclear. Here, Egfr mRNA was abundant in medullary portions of the UB trunk but absent from the branching UB tips during embryogenesis. Homozygous Egfr knockout did not affect the pattern of UB arborization, but renal papillae were hypoplastic and exhibited widespread apoptosis of tubular cells. Because these EGFR-deficient mice die within 1 week of life, we targeted Egfr inactivation to the renal collecting ducts using Cre-lox technology with a Hoxb7-Cre transgene. This targeted inactivation of Egfr led to a thin renal medulla, and at 7 weeks of age, the mice had moderate polyuria and reduced urine-concentrating ability. At 30 to 33 weeks, water deprivation demonstrated a continued urine-concentrating defect despite similar levels of vasopressin between knockout mice and littermate controls. Taken together, these results suggest that unlike other tyrosine kinases expressed at the UB tip, EGFR functions primarily to drive elongation of the emerging collecting ducts and to optimize urine-concentrating ability.