Results Identification a BAC containing known ChHV5 sequencesĪ BAC library was created from the glottis tumor of a Hawaiian green turtle with FP as described in Materials and Methods. Indeed, we found that the ChHV5 genome is largely collinear with the genomes of typical alphaherpesviruses but that is also comprises a number of unexpected features. The purpose of the research described here was to (1) generate a Bacterial Artificial Chromosome (BAC), , of ChHV5 and (2) expand the knowledge on ChHV5 genomic sequences. Having access to more sequence information about ChHV5 would be valuable in that it may open the doors for elucidation of molecular mechanisms of pathogenesis as well as for the development of diagnostic tests, antiviral treatments, and vaccines. Koch's postulates have not yet been fulfilled to identify conclusively ChHV5 as the one and only causative agent of FP, although transmission of FP by using cell-free tumor material has been reported. While descriptions of the clinical signs, pathology, and pathogenesis of FP are numerous, research on the FP-associated herpesvirus itself has been impeded by the fact that no cell culture system for propagation of ChHV5 exists and only a fraction of its genome has been sequenced all known sequences confining to the putative Unique Long (UL) fragment of the genome,. Furthermore, perivascular mononuclear cell infiltration has been observed frequently in the dermal layers of tumors. Rarely, amphophilic intranuclear inclusion bodies, compatible with herpesvirus, are noted in the epidermal layers of tumors suggesting that viral replication is restricted to certain areas of the tumor and, probably, to certain cell types. At present, it remains unclear, whether these alterations to the extracellular matrix are being caused by altered metabolism of the fibroblasts by transformation or directly by the function of unidentified viral enzymes that may be secreted from infected cells. All these tumor-types are ChHV5 DNA-positive and have extensive collagen deposition in the extracellular matrix with myxofibromas having deposition of sulfated proteoglycans between collagen fibers. Histologically, skin tumors are characterized as fibropapillomas, whereas internal tumors are characterized as fibromas, myxofibromas or fibrosarcomas of low grade malignancy. However, severe debilitation has also been observed with turtles carrying only few external or internal tumors. As a result of indirect effects of tumor growth, affected turtles become emaciated, bacteremic, immunosuppressed, and anemic. Tumor size may vary from 0.1 to more than 30 cm in diameter. Furthermore, tumors may grow in multiple visceral sites, including lung, liver, kidney, heart and gastrointestinal tract. FP is characterized by the formation of fibroepithelial tumors growing in the skin, in periorbital and orbital tissues, and in Hawaii, the oral cavity. In Florida, the prevalence of FP ranges from 11 to 52%. Since then, FP has reached epizootic proportions, affecting at least five more marine turtle species worldwide, including the east and west coast of both Northern and Southern America, the Caribbean, Australia, Asia, and the Hawaiian Islands (reviewed in, ). FP was first described in the 1930s in green sea turtles ( Chelonia mydas) from Florida. Based on previous partial sequencing of its genome, ChHV5 has been taxonomically assigned to the subfamily alphaherpesvirinae,. The Chelonid fibropapilloma-associated herpesvirus (CFPHV Chelonid herpesvirus 5, ChHV5) is strongly associated with fibropapillomatosis (FP), a neoplastic disease of marine turtles.
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