The role of peroxiredoxin III on late stage of proerythrocyte differentiation Hee-Young Yang a,c , Dong Kee Jeong d , Seok-Ho Kim a,c , Kyoung-Jin Chung b , Eun-Jin Cho a,c , Ung Yang c , Sang Ryeul Lee c , Tae-Hoon Lee c, * a Department of Molecular Medicine, Chonnam National University, Gwangju, South Korea b Graduate School of Biological Sciences and Technology, Chonnam National University, Gwangju, South Korea c Department of Oral Biochemistry, Dental Science Research Institute, The 2nd Stage of Brain Korea 21 for Dental School, Chonnam National University, Gwangju, South Korea d Department of Animal Science and Biotechnology, College of Applied Life Sciences, Cheju National University, Jeju, South Korea Received 30 May 2007 Available online 11 June 2007 Abstract Peroxiredoxin III (Prdx III), the mitochondrial peroxidase, was preferentially expressed in murine erythroleukemia (MEL) cells. However, the mechanisms by which Prdx III regulates erythroid differentiation are unknown. In this study, K562 cells were differenti- ated by Ara-C treatment, and Prdx III was dramatically increased until day 5. We also investigated Prdx III expression pattern on in vitro erythropoiesis of human CD34 + cells. When human CD34 + cells became proerythrocyte on day 7, Prdx III was diminished, and then augmented on day 12. We established the stable sublines of Prdx III overexpression (O/E), and dominant-negative (D/N). The intracellular ROS level of Prdx III O/E cell line was lower than D/N stable cell lines. Moreover, Prdx III O/E cell line was placed in G1-arrest, but not D/N cell lines. Finally, the expression level of b-globin and GATA-1 was dramatically increased in Prdx III O/E cell line. Ó 2007 Elsevier Inc. All rights reserved. Keywords: Peroxiredoxin III; Hematopoietic progenitor cells; Erythroid differentiation Peroxiredoxins (Prdxs) are a family of multifunctional antioxidant thioredoxin-dependent peroxidases that have been identified in a large variety of organisms [1–3]. The Prdx family includes six distinct isoforms, types I–VI, in mammalian cells. Among them, expression of Prdx III is ubiquitous, but, different from other peroxiredoxin mem- bers, Prdx III protein is abundantly localized in mitochon- dria [4,5]. Prdx III (MER-5, SP22, AOP-1) was originally isolated from murine erythroleukemia (MEL) cells, as a gene that is involved in erythroid cell differentiation [6]. DNA complementary to mRNA preferentially produced in MEL cells was cloned from a cDNA library of anemic mouse spleen mRNAs. An open-reading frame was noted in the cloned DNA, and was tentatively designated MER- 5 [7]. The levels of the Prdx III mRNA changed periodically during MEL cell differentiation. MEL cells exposed to DMSO accumulated RNA transcripts of globin and non- globine genes (c-myc, b-actin, MER-5) [8]. And also, when the Prdx III cDNA was transferred into MEL cells in both sense and antisense orientations, only in the transformants with the antisense Prdx III cDNA, did their elevated expres- sion inhibit differentiation [6]. Nevertheless, the function of Prdx III was unclear during erythrocyte differentiation. The human leukemia cell line K562 cells can be differen- tiated into erythrocytic commitment by chemically-induc- ing agents [9–11]. In our study, we used K562 because of its capacity to undergo erythroid lineages by cytosine arabinoside (Ara-C). Therefore, the present study 0006-291X/$ - see front matter Ó 2007 Elsevier Inc. All rights reserved. doi:10.1016/j.bbrc.2007.06.007 * Corresponding author. Address: Department of Biochemistry, School of Dentistry, Chonnam National University, 300 Yongbong-Dong, Buk- Ku, Gwangju 500-757, South Korea. Fax: +82 62 5304809. E-mail address: thlee83@chonnam.ac.kr (T.-H. Lee). www.elsevier.com/locate/ybbrc Biochemical and Biophysical Research Communications 359 (2007) 1030–1036