title: Host responses of Japanese flounder Paralichthys olivaceus with lymphocystis cell formation.
abstract: Lymphocystis disease virus (LCDV) is the causative agent of lymphocystis disease (LCD). In this study, we investigated the mechanisms of lymphocystis cell (LCC) formation from the viewpoint of gene expression changes in the infected fish. LCC occurrence and virus titers in the experimentally infected Japanese flounder, Paralichthys olivaceus were monitored by visual confirmation and real-time PCR, respectively. The gene expression changes in the fish fin were investigated by microarray experiments. LCCs firstly appeared in the fish at 21 days post infection (dpi). LCD incidence increased with time and reached 92.9% at 62 dpi. LCDV genome was firstly detected from dorsal fins at 14 dpi, and the relative amount of the genome gradually-increased until 56 dpi. Since the occurrence of LCC was approximately synchronized with increasing of the virus genome, virus replication might play important roles for LCC formation. The microarray detected a few gene expression changes until 28 dpi. However, the number of expression changed genes dramatically increased between 28 and 42 dpi in which LCCs formation was active. From the microarray data analyses, apoptosis and cell division related genes were down-regulated, whereas cell fusion and collagen related genes were up-regulated at 42 dpi. Together with the observation of morphological changes of LCCs in previous reports, it is suggested that the following steps are involved in LCC formation: the virus infected cells were (1) inhibited apoptotic death and (2) cell division before enlargement, (3) hypertrophied by cell fusion, and (4) surrounded by a hyaline capsule associated with the alteration of collagen fibers.
authors.affiliation: Graduate School of Science and Engineering, Ehime University, Matsuyama 790-8577, Japan; Centre for Marine Environmental Studies (CMES), Ehime University, Matsuyama 790-8577, Japan.
authors.forename: Shogo
authors.initials: S
authors.lastname: Iwakiri
authors.affiliation: Pathology Division, National Fisheries Research and Development Institute, Busan 619-902, Republic of Korea.
authors.forename: Jun-Young
authors.initials: JY
authors.lastname: Song
authors.affiliation: Centre for Marine Environmental Studies (CMES), Ehime University, Matsuyama 790-8577, Japan.
authors.forename: Kei
authors.initials: K
authors.lastname: Nakayama
authors.affiliation: Department of Aqualife Medicine, Chonnam National University, Yeosu 550-749, Republic of Korea.
authors.forename: Myung-Joo
authors.initials: MJ
authors.lastname: Oh
authors.affiliation: Fisheries Research Center, Ehime Research Institute of Cultivation Resources, Ehime Research Institute of Agriculture, Forestry and Fisheries, Iyo 799-3125, Japan.
authors.forename: Minoru
authors.initials: M
authors.lastname: Ishida
authors.affiliation: Graduate School of Science and Engineering, Ehime University, Matsuyama 790-8577, Japan; Centre for Marine Environmental Studies (CMES), Ehime University, Matsuyama 790-8577, Japan. Electronic address: kitamura@ehime-u.ac.jp.
authors.forename: Shin-Ichi
authors.initials: S
authors.lastname: Kitamura
mesh_terms: D058500:Animal Fins / Q000821:virology; D000818:Animals; D017209:Apoptosis; D004266:DNA Virus Infections / Q000235:genetics / Q000276:immunology / Q000662:veterinary* / Q000821:virology; D004817:Epidermis / Q000821:virology; D005393:Fish Diseases / Q000235:genetics / Q000276:immunology* / Q000821:virology; D005412:Flatfishes; D005786:Gene Expression Regulation; D007497:Iridoviridae / Q000276:immunology*; D040081:Protein Array Analysis; D060888:Real-Time Polymerase Chain Reaction / Q000662:veterinary; D012871:Skin Diseases / Q000235:genetics / Q000276:immunology / Q000662:veterinary / Q000821:virology
keywords: Apoptosis; Lymphocystis disease; Lymphocystis disease virus; Microarray