The structure of the mouse mammary tumor virus: Isolation and characterization of the core

Y. A. Teramoto, Robert Cardiff, J. K. Lund

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A number of different conditions were evaluated to obtain a quantitatively efficient isolation procedure for the production of mouse mammary tumor virus (MMTV) cores. The efficiency of each procedure was determined by the recovery of radiolabeled MMTV-RNA in particles with a density of 1.24 - 1.26 g/cm3. Maximum recoveries of 40-60% were obtained with pretreatment of virions with 0.5 - 1% nonionic detergent at 37° for 15 min followed by isopycnic centrifugation. The resulting particles were morphologically identical to the internal core structure of MMTV virions and contained 60-70 S RNA and reverse transcriptase. The isolated cores were analyzed by immunodiffusion and by sodium dodecyl sulfate (SDS)-polyacrylamide-gel electrophoresis. The major polypeptides of the cores were p30, p28, and p14. Two polypeptides, p28 and p14, were also major virion polypeptides. The emergence of p30 as a major core polypeptide was considered to be from interconversion and selective retention of other MMTV polypeptides. The envelope glycoproteins could not be identified among the many minor polypeptides.

Original languageEnglish (US)
Pages (from-to)135-148
Number of pages14
Issue number1
StatePublished - Jan 1 1977


ASJC Scopus subject areas

  • Virology

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