Analysis of the role of Nrf2 in the expression of liver proteins in mice using two-dimensional gel-based proteomics Azman Abdullah 1,3# , Neil R. Kitteringham 1# , Rosalind E. Jenkins 1 , Christopher Goldring 1 , Larry Higgins 2 , Masayuki Yamamoto 4 , John Hayes 2 , B. Kevin Park 1 Department of Pharmacology, University of Liverpool, Sherrington Buildings, Liverpool, Merseyside, L69 3GE, United Kingdom Biomedical Research Centre, Ninewells Hospital and Medical School, University of Dundee, Dundee DD1 9SY, Scotland, United Kingdom Department of Pharmacology, Faculty of Medicine, Universiti Kebangsaan Malaysia, Jalan Raja Muda Abdul Aziz, 50300 Kuala Lumpur, Malaysia The Centre for Tsukuba Advanced Research Alliance and Institute of Basic Medical Sciences, University of Tsukuba, Tsukuba 305-8577, Japan Correspondence: Azman Abdullah, e-mail: manlah1969@yahoo.com Abstract: Background: The transcription factor Nrf2 regulates expression of multiple cellular defence proteins through the antioxidant re- sponse element (ARE). Nrf2-deficient mice (Nrf2 ) are highly susceptible to xenobiotic-mediated toxicity, but it is not known whether this reflects low basal expression or reduced inducibility of Nrf2-regulated genes in response to chemical insults. Methods: Wild type and Nrf2 mice were fed diet supplemented with the established Nrf2 inducer butylated hydroxyanisole (BHA) [0.5% (w/w)] for 14 days. To define the range of Nrf2-regulated proteins, both basally and following exposure to BHA, a comparison of the liver proteomes of Nrf2 and wild type mice was conducted. The two-dimensional gel electrophoresis (2-DE) technique and MALDI mass spectrometry were utilized in the attempt to define Nrf2-regulated proteins. Results: Overall, 24 proteins were identified, which were regulated either basally (3 proteins), inducibly (16 proteins), or both (5 proteins). These included several well-established Nrf2-driven gene products e.g., aldo-keto reductase and glutathione transfe- rases. Multiple consensus ARE/ARE-like sequences were found in the Nrf2-regulated genes. Conclusions: This study confirms the central role of Nrf2 in the induction of multiple defense proteins as well as its control in the constitutive expression of certain proteins. Key words: Nrf2, transgenic, mouse, liver, protein expression, two-dimensional gel electrophoresis 680 Authors contributed equally to this work