title: A new retrovirus produced by tissue culture cell line from mammary tumor of a house musk shrew, Suncus murinus.
abstract: A new type of retrovirus (Sm-MTV) released by cultured cells of a spontaneous mammary tumor from a house musk shrew, Suncus murinus, is described. The Sm-MTV is distinct morphologically from type C particles. In spite of certain morphological similarities to type B and type D retroviruses, the Sm-MTV is readily distinguishable. The extracellular virions had a spikeless envelope containing a centrally located nucleoid with a small electron-dense core surrounded by an inner membrane. The budding particles contained a doughnut-shaped nucleoid. Intracytoplasmic type A particles similar in profile to those associated with mouse mammary tumor cells were also found, and tended to form a small cluster of several particles in the cytoplasm. The virus banded at 1.169 g/cm3 in isopycnic centrifugation and possessed constitutive Mg2+-dependent reverse transcriptase. The viral RNA had a molecular size ranging from 50 to 70 S in its native form and 30 to 40 S in its denatured form by a glycerol gradient ultracentrifugation. Major viral polypeptides were 72K, 69K, 47K, 44K/43K, 27K, 20.5K, and 15K.
mesh_terms: D000818:Animals; D002460:Cell Line; D008325:Mammary Neoplasms, Experimental / Q000382:microbiology*; D008854:Microscopy, Electron; D008970:Molecular Weight; D012367:RNA, Viral / Q000302:isolation & purification; D012190:Retroviridae / Q000302:isolation & purification* / Q000648:ultrastructure; D012788:Shrews / Q000382:microbiology*; D013045:Species Specificity; D014764:Viral Proteins / Q000302:isolation & purification
chemical_list: D012367:RNA, Viral; D014764:Viral Proteins