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The mature reverse transcriptase molecules in virions of mouse mammary tumor virus possess protease-derived sequences

Michal Entin-Meer1, Orna Avidan, Amnon Hizi

  • 1Department of Cell Biology and Histology, Sackler School of Medicine, Tel Aviv University, Tel Aviv 69978, Israel.

Virology
|June 6, 2003
PubMed

Insights

Mouse mammary tumor virus reverse transcriptase (RT) requires additional sequences for activity. Studies show the mature MMTV RT in virions contains protease-derived sequences at its amino-terminus, supporting its transframe nature.

Area of Science:

  • Virology
  • Molecular Biology
  • Biochemistry

Background:

  • Enzymatically active reverse transcriptase (RT) from mouse mammary tumor virus (MMTV) requires specific amino acid sequences for function.
  • Previous studies indicated that MMTV RT is active only when fused with 27 residues from the pro gene's terminus.

Purpose of the Study:

  • To investigate whether the mature MMTV RT found in virions is fused with protease-derived sequences.
  • To further explore the transframe nature of MMTV RT.

Main Methods:

  • Analysis of MMTV RT molecules within virions.
  • Utilized two antisera targeting peptides from the MMTV protease's carboxyl-terminus and the MMTV RT's middle section.

Main Results:

  • Data suggest that the mature MMTV RT in virions possesses sequences from the carboxyl-terminus of the MMTV protease at its amino-terminus.
  • This indicates a fusion between protease and RT components.

Conclusions:

  • The findings support the hypothesis that MMTV RT is a transframe protein, originating from both the pro and pol reading frames.
  • Specific protease residues are utilized as integral parts of both the protease and RT enzymes, highlighting dual functionality.

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