Jaagsiekte sheep retrovirus: A BETARETROVIRUS that causes pulmonary adenomatosis in sheep (PULMONARY ADENOMATOSIS, OVINE).Pulmonary Adenomatosis, Ovine: A contagious, neoplastic, pulmonary disease of sheep characterized by hyperplasia and hypertrophy of pneumocytes and epithelial cells of the lung. It is caused by JAAGSIEKTE SHEEP RETROVIRUS.Betaretrovirus: A genus of the family RETROVIRIDAE consisting of viruses with either type B or type D morphology. This includes a few exogenous, vertically transmitted and endogenous viruses of mice (type B) and some primate and sheep viruses (type D). MAMMARY TUMOR VIRUS, MOUSE is the type species.Sheep: Any of the ruminant mammals with curved horns in the genus Ovis, family Bovidae. They possess lachrymal grooves and interdigital glands, which are absent in GOATS.Hyaluronoglucosaminidase: An enzyme that catalyzes the random hydrolysis of 1,4-linkages between N-acetyl-beta-D-glucosamine and D-glucuronate residues in hyaluronate. (From Enzyme Nomenclature, 1992) There has been use as ANTINEOPLASTIC AGENTS to limit NEOPLASM METASTASIS.Endogenous Retroviruses: Retroviruses that have integrated into the germline (PROVIRUSES) that have lost infectious capability but retained the capability to transpose.Sheep Diseases: Diseases of domestic and mountain sheep of the genus Ovis.Gene Products, env: Retroviral proteins, often glycosylated, coded by the envelope (env) gene. They are usually synthesized as protein precursors (POLYPROTEINS) and later cleaved into the final viral envelope glycoproteins by a viral protease.Cell Transformation, Viral: An inheritable change in cells manifested by changes in cell division and growth and alterations in cell surface properties. It is induced by infection with a transforming virus.Goats: Any of numerous agile, hollow-horned RUMINANTS of the genus Capra, in the family Bovidae, closely related to the SHEEP.Terminal Repeat Sequences: Nucleotide sequences repeated on both the 5' and 3' ends of a sequence under consideration. For example, the hallmarks of a transposon are that it is flanked by inverted repeats on each end and the inverted repeats are flanked by direct repeats. The Delta element of Ty retrotransposons and LTRs (long terminal repeats) are examples of this concept.Receptors, Virus: Specific molecular components of the cell capable of recognizing and interacting with a virus, and which, after binding it, are capable of generating some signal that initiates the chain of events leading to the biological response.GPI-Linked Proteins: A subclass of lipid-linked proteins that contain a GLYCOSYLPHOSPHATIDYLINOSITOL LINKAGE which holds them to the CELL MEMBRANE.Viral Envelope Proteins: Layers of protein which surround the capsid in animal viruses with tubular nucleocapsids. The envelope consists of an inner layer of lipids and virus specified proteins also called membrane or matrix proteins. The outer layer consists of one or more types of morphological subunits called peplomers which project from the viral envelope; this layer always consists of glycoproteins.Lung Neoplasms: Tumors or cancer of the LUNG.Adenocarcinoma, Bronchiolo-Alveolar: A carcinoma thought to be derived from epithelium of terminal bronchioles, in which the neoplastic tissue extends along the alveolar walls and grows in small masses within the alveoli. Involvement may be uniformly diffuse and massive, or nodular, or lobular. The neoplastic cells are cuboidal or columnar and form papillary structures. Mucin may be demonstrated in some of the cells and in the material in the alveoli, which also includes denuded cells. Metastases in regional lymph nodes, and in even more distant sites, are known to occur, but are infrequent. (From Stedman, 25th ed)Cell Line: Established cell cultures that have the potential to propagate indefinitely.DNA, Viral: Deoxyribonucleic acid that makes up the genetic material of viruses.Lung: Either of the pair of organs occupying the cavity of the thorax that effect the aeration of the blood.