Genetic Disorders – Development
Kidney International (2002) 62, 763–769; doi:10.1046/j.1523-1755.2002.00533.x
Tornado extraction: A method to enrich and purify RNA from the nephrogenic zone of the neonatal rat kidney
Takahito Ito, Akira Suzuki, Enyu Imai, Naoko Horimoto, Tomokazu Ohnishi, Yasushi Daikuhara and Masatsugu Hori
Osaka University Graduate School of Medicine, Department of Internal Medicine and Therapeutics, Osaka, and Kagoshima University Dental School, Department of Biochemistry, Kagoshima, Japan
Correspondence: Takahito Ito, M.D., Department of Internal Medicine and Therapeutics, Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Box A8, Suita, Osaka 565-0871, Japan. E-mail: taka@medone.med.osaka-u.ac.jp
Received 28 August 2001; Revised 1 April 2002; Accepted 22 April 2002.
Abstract
Tornado extraction: A method to enrich and purify RNA from the nephrogenic zone of the neonatal rat kidney.
Background
Development of the kidney is a complicated and tightly regulated process. Although several genes responsible for the renal development have been identified to date, the precise mechanisms of spatial and temporal regulation remain to be elucidated. Therefore, expanding our knowledge of molecules that are associated with nephrogenesis will be helpful to understand the whole process.
Methods
To extract RNA selectively from the nephrogenic zone of the developing kidney, we developed a simple and reliable method.
Results
This method, named "tornado extraction," enriched RNA of the nephrogenic zone by about 30-fold. In combination with the suppression subtractive hybridization, a considerable number of genes that were differentially expressed in the nephrogenic zone were obtained. These genes included a series of endodermal markers such as albumin and 
-fetoprotein as well as GDNF (glia-derived neurotrophic factor), osteoblast-specific factor-2 (OSF-2)/periostin and fetuin (one of the major serum proteins in the fetus).
Conclusion
Tornado extraction has great value in studying genes in the nephrogenic zone of the developing kidney. Since the quality of RNA obtained by this method is excellent, tornado extraction is suitable in combination with other techniques including the subtractive hybridization method and DNA microarray analysis.
Keywords:
nephrogenesis, subtractive hybridization, microarray, embryonic kidney, renal development
