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Gene order of the mouse mammary tumor virus glycoproteins

G Schochetman1, S Oroszlan, L Arthur

  • 1Viral Oncology Program, National Cancer Institute Frederick Cancer Research Center, Frederick, Maryland 21701, USA.

Virology
|November 1, 1977
PubMed

Insights

Mouse mammary tumor virus (MMTV) envelope glycoproteins gp52 and gp36 originate from a single precursor. Researchers determined the gene order of these MMTV proteins using three distinct experimental methods.

Area of Science:

  • Virology
  • Molecular Biology
  • Biochemistry

Background:

  • Mouse mammary tumor virus (MMTV) is a retrovirus known to express envelope glycoproteins.
  • Understanding the structure and genomic organization of viral proteins is crucial for studying viral replication and pathogenesis.

Purpose of the Study:

  • To determine the gene order of MMTV envelope glycoproteins gp52 and gp36 within the viral genome.
  • To elucidate the precursor-product relationship between MMTV envelope glycoproteins.

Main Methods:

  • Immunochemical techniques and tryptic peptide mapping were employed to analyze MMTV envelope glycoproteins.
  • Differential inhibition by NaCl hypertonic shock was used to study protein synthesis initiation.
  • Analysis of protein synthesis kinetics and polyribosome-released polypeptides provided further data.

Main Results:

  • MMTV envelope glycoproteins gp52 and gp36 are distinct components derived from a common glycosylated precursor polypeptide of 75,000 daltons (gPr75).
  • The gene order within the MMTV genome was established as 5'-gp52-gp36-3', with the polypeptide orientation H2N-gp52-gp36-COOH.

Conclusions:

  • The study successfully determined the gene order of MMTV envelope glycoproteins gp52 and gp36.
  • These findings contribute to the understanding of MMTV gene expression and protein processing.

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