Journal of Trace Elements in Medicine and Biology 23 (2009) 124–131 MOLECULAR BIOLOGY Differential quantitative zinc-induced expression of human metallothionein isogenes in haematopoietic precursor cell lines Pegah Maghdooni Bagheri a , Mohammad Tariqur Rahman b , Sofie Van Soest c , Marc De Ley a,Ã a Laboratory for Biochemistry, Department of Chemistry, Katholieke Universiteit Leuven, Celestijnenlaan 200G, mailbox 2413, B-3001 Leuven (Heverlee), Belgium b Department of Biomedical Science, International Islamic University Malaysia, Jalan Istana, Kuantan 25200, Pahang, Malaysia c Laboratory of Developmental Physiology, Genomics and Proteomics, Zoological Institute, Katholieke Universiteit Leuven, Naamsestraat 59, 3000 Leuven, Belgium Received 7 November 2008; accepted 13 February 2009 Abstract The expression pattern of functional members of the metallothionein (MT) gene family was studied in the haematopoietic precursor cell lines, K562, DAMI, MEG-01, and ELF-153 in order to strengthen the proposed function of MT in differentiation. Cells were cultured in RPMI 1640 with 10% (v/v) foetal calf serum, with or without different zinc supplements. Expression of MT isogenes was analysed by quantitative real-time PCR (RT-PCR) using mRNA extracted from cultured cells. The more mature K562, DAMI, and MEG-01 cell lines exhibited transcription of all MT isogenes, except MT-3 and MT-4. Relative quantitative expression of MT isogenes in the mature cell lines such as K562, DAMI, and MEG-01 was higher than in the immature ELF-153 cell line. Immunohistochemical staining (IHC) reveals an increased MT protein biosynthesis in more mature cell lines such as K562, DAMI and MEG-01 greater than in the immature ELF-153 cell line. Real-time PCR and immunohistochemical staining for investigating the effect of phorbol ester and hemin (haematopoietic differentiation stimuli) on expression of MT isogenes in K562 cells reveals that phorbol ester induces increased MT transcription and biosynthesis. Therefore, to our knowledge, the role of MT in differentiation in human haematopoietic precursor cell lines is here reported for the first time. r 2009 Elsevier GmbH. All rights reserved. Keywords: Haematopoietic differentiation; Megakaryocytic cell lines; Metallothionein; Phorbol ester; Zinc Introduction Zinc (Zn) is an essential trace element for all forms of life. It plays an important role in growth and develop- ment, immune response, neurological function, and reproduction. On the cellular level, Zn has a catalytic role in Zn-dependent enzymes, a structural role in Zn fingers, other proteins and cell membranes, and a regulatory role in transcription factors, cell signalling ARTICLE IN PRESS www.elsevier.de/jtemb 0946-672X/$ - see front matter r 2009 Elsevier GmbH. All rights reserved. doi:10.1016/j.jtemb.2009.02.003 Abbreviations: DMSO, dimethyl sulfoxide; FCS, foetal calf serum; GAPDH, glyceraldehyde-3-phosphate dehydrogenase; IL-3, interleu- kin-3; IHC, immunohistochemical staining; MT, metallothionein; MTF-1, metal-responsive transcription factor-1; PMA, phorbol-12 myristate-13 acetate. Ã Corresponding author. Tel.: +32 16 327317; fax: +32 16 327978. E-mail addresses: tarique@iiu.edu.my (M.T. Rahman), Marc.DeLey@chem.kuleuven.be (M. De Ley).