A virus-like agent associated with neurofibromatosis in damselfish

Abstract

Damselfish neurofibromatosis (DNF) is a transmissible disease involving neurofibromas and chromatophoromas affecting bicolor damselfish Stegastes partitus on Florida reefs. Analysis of genomic DNA by Southern blotting techniques demonstrated the presence of a group of extrachromosomal DNAs in tumors from fish affected with DNF but not in healthy individuals. Cell lines obtained from tumors contained identical DNAs and were shown to be tumorigenic in vivo, while lines established from healthy fish did not contain such DNA and were not tumorigenic. These DNA patterns were also observed in experimentally induced tumors. A DNase resistant component of this DNA was isolated from both tumor cells and conditioned media of tumor cell lines suggesting that these sequences were encapsulated in viral particles. These data support the hypothesis that one or more of these extrachromosomal DNA forms is the genome of an unusual virus and that this virus is the etiologic agent of DNF. We have tentatively termed this agent the damselfish virus-like agent (DVLA).KEY WORDS: Neurofibroma · Damselfish · Tumor · Virus · Schwann Cell · Chromatophore Resale or republication not permitted without written consent of the publisherDis Aquat Org 49: [107][108][109][110][111][112][113][114][115] 2002 lines maintained in culture for many years, indicating that DNF is caused by a sub-cellular infectious agent (Schmale 1995). We have previously demonstrated the presence of several retroviruses in damselfish cell lines (Schmale et al. 1996 and unpubl. data). However, retroviral genomes could not be detected consistently in damselfish tumors or other tissues and thus cannot be considered a likely etiologic agent of this disease.In this study we report the occurrence of a group of extrachromosomal DNAs (eDNA) in tumors from fish affected with DNF but not in healthy individuals. We have determined the distribution of this eDNA in both tumor bearing and healthy fish, and cell lines derived from such fish, and conducted in vivo transmission studies to investigate the relationship of these DNAs to tumorigenesis. We have also assessed resistance to DNase treatment as an indicator of possible encapsulation of this eDNA into intra-or extracellular particles. MATERIALS AND METHODSDamselfish and cell cultures. Bicolor damselfish Stegastes (previously Pomacentrus) partitus were collected on reefs in South Florida which had previously been surveyed to determine disease prevalence rates (Schmale 1991). Healthy fish used for experimental tumor induction were collected from a single low disease prevalence reef, Fowey Rocks. Fish were maintained in either recirculating or flow-through marine aquaria of ≥ 35 l at 20-30°C. Normal fish were observed in the laboratory for several weeks following capture to confirm initial observations that they lacked any signs of DNF. DNF was identified by visual inspection for external tumors as described in Schmale et al. (1986). Spontaneous tumors were obtained from fish with DNF collected in the wild. Fish were eut...

Genetic connectivity of Stegastes partitus in the South Caribbean evidenced by microsatellite analysis

“…También sería recomendable adelantar estudios que permitan estimar el tamaño efectivo poblacional para detectar poblaciones que no podrían contrarrestar los efectos de la deriva en ausencia de flujo genético (Lacy 1987) y no perder de vista factores adversos como enfermedades (Schmale et al 2002) o eventos catastróficos (Lacson y Morizot 1991) que podrían convertirse en una amenaza para estas poblaciones del Caribe por el efecto sinérgico.…”

“…It is therefore important to try to maintain the present levels of connectivity. It is also important to undertake studies in order to estimate the effective population size necessary to detect populations that may not counteract the effects of genetic drift or lack of gene flow (Lacy 1987), and to keep in mind other adverse factors such as sickness (Schmale et al 2002) or catastrophic events (Lacson and Morizot 1991) that could represent a threat for these populations due to synergistic effects. mitocondrial NADH1 (Rocha et al 2006), sugiriendo que los resultados no son probablemente una consecuencia de los marcadores genéticos utilizados.…”

Diseases and Mortalities of Fishes and Other Animals in The Gulf of Mexico

“…The lesion has been considered as a model for neurofibromatosis (von Recklinghausen's disease) in humans. Subsequently, it was found that the disease was transmissible from tumor-bearing to non-tumor-bearing specimens through tissue homogenates (Schmale and Hensley 1988) and that a virus-like agent, probably a retrovirus (Schmale et al 1996), was responsible for the disease in damselfish (Schmale et al 2002). Lucke (1942) reported similar nerve sheath neoplasms at a prevalence of 0.5-1.0 % in three snapper species from the Dry Tortugas near Key West.…”

Epizootics and Disease of Coral Reef Fish in the Tropical Western Atlantic and Gulf of Mexico

“…Damselfish neurofibromatosis (DNF) is one of the most extensively studied diseases of coral reef fishes (Schmale, 1991;Schmale et al, , 2002. The bicolor damselfish Stegastes partitus is a tropical marine fish on south Florida reefs that appears to be naturally affected by multiple neurofibromas, neurofibrosarcomas, and chromatophoromas.…”