title: Identification of Appropriate Housekeeping Genes for Gene Expression Analysis in Long-term Hypoxia-treated Kidney Cells.
abstract: BACKGROUND
  Selection of stably expressing housekeeping genes (HKGs) is a crucial step in gene expression analysis. However, there are no universal HKGs for all experiments, and they should be determined by each biologic condition. The aim of this study was to detect appropriate HKGs for kidney cells cultured in long-term hypoxia.
  
  
  METHODS
  Based on a screening step using a microarray data available from gene expression omnibus database, a set of candidate HKGs were chosen to be assessed in human kidney cells cultured in hypoxic or normoxic conditions for about 2 weeks in a time course manner. The stability of gene expression was assessed by refFinder, a web-based tool that integrates four computational programs (geNorm, Normfinder, BestKeeper, and the comparative ΔΔCt method).
  
  
  RESULTS
  GAPDH and ACTB were the most stable genes in hypoxia treated cells whereas, B2M and ACTB were the best HKGs in cells cultured in normoxia. When both hypoxia and normoxia treated cells from all time points were evaluated together, GAPDH and ACTB equally showed the most stability.
  
  
  CONCLUSIONS
  As in relative quantification of real-time polymerase chain reaction data, the same HKGs should be selected for all groups, we believe that GAPDH and ACTB are suitable HKGs for studies on the effect of hypoxia on cultured kidney cells.
authors.affiliation: Department of Genetics and Molecular Biology, Isfahan University of Medical Sciences, Isfahan, Iran.
authors.forename: Shiva
authors.initials: S
authors.lastname: Moein
authors.affiliation: Applied Physiology Research Center, Isfahan University of Medical Sciences, Isfahan, Iran.
authors.forename: Shaghayegh Haghjooy
authors.initials: SH
authors.lastname: Javanmard
authors.affiliation: Department of Genetics and Molecular Biology, Isfahan University of Medical Sciences, Isfahan, Iran.
authors.forename: Maryam
authors.initials: M
authors.lastname: Abedi
authors.affiliation: Department of Urology, Isfahan University of Medical Sciences, Isfahan, Iran.
authors.forename: Mohammad Hosein
authors.initials: MH
authors.lastname: Izadpanahi
authors.affiliation: Department of Genetics and Molecular Biology, Isfahan University of Medical Sciences, Isfahan, Iran; Regenerative Medicine Lab, Isfahan Kidney Diseases Research Center, Isfahan University of Medical Sciences, Isfahan, Iran.
authors.forename: Yousof
authors.initials: Y
authors.lastname: Gheisari
keywords: Gene expression analysis; housekeeping gene; hypoxia; kidney