ABSTRACT
E5 protein, the major oncoprotein of the bovine Deltapapillomavirus genus, has been detected in 17 of the 19 urothelial cancers by molecular and morphological procedures. In 10 urothelial cancers, the oxygen sensitive subunit HIF-1α, which is upregulated by hypoxia, was overexpressed. Mitophagy, the selective autophagic removal of dysfunctional mitochondria, was upregulated in hypoxic neoplastic cells infected by BPVs which was mediated by FUNDC1, a mitochondrial outer-membrane protein. The FUNDC1 receptor was amplified by PCR, and amplicon sequencing showed a 100% homology with bovine FUNDC1 sequences deposited in GenBank (accession number: NM_001104982). Both transcripts and protein levels of FUNDC1 were significantly decreased in hypoxic neoplastic cells relative to healthy, non-neoplastic cells. FUNDC1 interacted with the LC3 protein, a marker of autophagosome (mitophagosome) membrane, the Hsc70/Hsp70 chaperone, and Bag3 co-chaperone. Bag3 may play a role in mitophagosome formation together with the Synpo2 protein, and may be involved in the degradation of Hsc70/Hsp70-bound CHIP-ubiquitinated cargoes, in association with its chaperone. Ultrastructural findings revealed the presence of mitochondria exhibiting severe fragmentation and loss of cristae, as well as numerous mitochondria-containing autophagosomes. Total and phosphorylated GTPase dynamin-related protein 1 (DRP1), which plays a crucial role in mitochondrial fission, a pre-requisite for mitophagy, was overexpressed at the mitochondrial level. Total and phosphorylated mitochondrial fission factor (Mff), mitochondrial fission protein 1 (Fis1), mitochondrial dynamics 51 (MiD51), and MiD49, which are DRP1 receptors responsible and/or co-responsible for its mitochondrial recruitment were overexpressed.
Subject(s)
Deltapapillomavirus/pathogenicity , Mitochondria/pathology , Mitochondrial Proteins/metabolism , Mitophagy , Urothelium/virology , Animals , Cattle , Female , GTP-Binding Proteins/genetics , Hypoxia , Microscopy, Electron, Transmission , Mitochondria/ultrastructure , Mitochondria/virology , Mitochondrial Proteins/genetics , Oncogene Proteins, Viral/genetics , Phosphorylation , Urothelium/cytology , Urothelium/pathologySubject(s)
Deltapapillomavirus/pathogenicity , Papilloma/veterinary , Papillomavirus Infections/veterinary , Skin Neoplasms/veterinary , Animals , Animals, Domestic , Cattle , Keratinocytes/pathology , Keratinocytes/virology , Papilloma/pathology , Papilloma/virology , Papillomavirus Infections/pathology , Papillomavirus Infections/virology , Skin Neoplasms/pathology , Skin Neoplasms/virologyABSTRACT
Bovine papillomaviruses (BPVs) are recognized as causal agents of benign and malignant tumors in cattle. Thirteen types of BPVs have already been described and classified into 3 distinct genera. Divergences in the nucleotide sequence of the L1 gene are used to identify new viral types through the employment of PCR assays with degenerated primers. In the present study, a method for identifying BPVs based on PCR-RFLP and DNA sequencing allowed the identification of a new putative Deltapapillomavirus, designated JN/3SP (JQ280500.1). The analysis of the L1 gene showed that this strain was most closely related to the BPVs -1, -2, -13 , and OaPV1 (71-73% genetic similarity). In this study, we describe the detection of this new putative Deltapapillomavirus type and verify its phylogenetic position within the genus.
