Short communication Molecular characterization of two immunity-related acute-phase proteins: Haptoglobin and serum amyloid A from black rockfish (Sebastes schlegeli) Q3 Q2 J.D.H.E. Jayasinghe a, b , Don Anushka Sandaruwan Elvitigala a, b , Ilson Whang a, b , Bo-Hye Nam c , Jehee Lee a, b, * a Department of Marine Life Sciences, School of Marine Biomedical Sciences, Jeju National University, Jeju Self-Governing Province 690-756, Republic of Korea b Fish Vaccine Development Center, Jeju National University, Jeju Special Self-Governing Province 690-756, Republic of Korea c Biotechnology Research Division, National Fisheries Research and Development Institute, 408-1 Sirang-ri, Gijang-up, Gijang-gun, Busan 619-705, Republic of Korea article info Article history: Received 25 February 2015 Received in revised form 4 May 2015 Accepted 10 May 2015 Available online xxx Keywords: Haptoglobin Serum amyloid A Black rockfish Immune challenge Transcriptional response abstract Haptoglobin (Hp) and serum amyloid A (SAA) are two vital proteins involved in inflammatory reactions and are classified as acute-phase proteins. They are released from hepatocytes under inflammatory conditions to protect healthy cells from being damaged by pathogens or from self-destructive mechanisms. In this study, a previously constructed black rockfish (Sebastes schlegeli) cDNA library was used to identify the full-length cDNA sequences of Hp and SAA homologs (RfHp and RfSAA, respectively) and characterize them at the molecular level. As expected, in silico analysis of these homologs showed the typical domain architectures of their known counterparts. Open reading frames of RfHp and RfSAA consisted of 942-bp and 313-bp DNA sequences, respectively. The derived polypeptide sequence of RfHp was composed of 313 amino acids (aa) with a predicted molecular weight of 34 kD, whereas RfSAA had a 121-amino acid sequence with a molecular weight of 13 kD. Phylogenetic analysis as well as pairwise sequence alignment results showed that RfHp was more closely related to Oreochromis mossambicus from an evolutionary perspective while RfSAA was closely related to the Epinephelus coioides ortholog. Although both genes were expressed ubiquitously in the tissues analyzed, they were particularly expressed in liver tissue, suggesting their origin in hepatocytes. Quantitative real-time PCR analysis indicated that both RfHp and RfSAA were significantly up-regulated by both bacterial and viral stimulation in liver tissue, affirming their putative importance in the acute phase of first-line host immune defenses. © 2015 Published by Elsevier Ltd. 1. Introduction The immune system has two major subdivisions, innate and acquired, classified according to how pathogens are recognized [1,2]. Innate immunity plays a pivotal role as the first-line host defense mechanism until adaptive immunity begins its role in immune response [3]. Innate immunity is essential for the survival of fish for many reasons, such as their limited number of antibodies, limited affinity maturation, relatively slow lymphocyte prolifera- tion, and their poikilothermic nature [2]. At the onset of inflammation, the acute phase response (APR) mediated by pro-inflammatory factors is activated, resulting in the destruction of contaminants or infectious agents, removal of damaged tissues, and repair of affected organs to restore physio- logical homeostasis [4,5]. APR has been identified as a core part of innate immunity especially in invertebrates and fish, in which it is comparatively strong, compensating the limitations of their adap- tive immune system [2,6]. As a result of the APR, certain plasma proteins known as acute-phase proteins (APP) are released from liver and increased in concentration by at least 25% in the acute * Corresponding author. Marine Molecular Genetics Lab, Department of Marine Life Sciences, College of Ocean Science, Jeju National University, 66 Jejudaehakno, Ara-Dong, Jeju 690-756, Republic of Korea. Tel.: þ82 64 754 3472; fax: þ82 64 756 3493. E-mail address: jehee@jejunu.ac.kr (J. Lee). Contents lists available at ScienceDirect Fish & Shellfish Immunology journal homepage: www.elsevier.com/locate/fsi http://dx.doi.org/10.1016/j.fsi.2015.05.020 1050-4648/© 2015 Published by Elsevier Ltd. Fish & Shellfish Immunology xxx (2015) 1e9 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 YFSIM3455_proof ■ 22 May 2015 ■ 1/9 Please cite this article in press as: J.D.H.E. Jayasinghe, et al., Molecular characterization of two immunity-related acute-phase proteins: Haptoglobin and serum amyloid A from black rockfish (Sebastes schlegeli), Fish & Shellfish Immunology (2015), http://dx.doi.org/10.1016/ j.fsi.2015.05.020