Inhibition of reverse transcription in vivo by elevated manganese ion concentration

Mol Cell. 2002 Apr;9(4):879-89. doi: 10.1016/s1097-2765(02)00495-1.

Abstract

Mutations in PMR1, a yeast gene encoding a calcium/manganese exporter, dramatically decrease Ty1 retrotransposition. Ty1 cDNA is reduced in pmr1 mutant cells, despite normal levels of Ty1 RNA and proteins. The transposition defect results from Mn(2+) accumulation that inhibits reverse transcription. Cytoplasmic accumulation of Mn(2+) in pmr1 cells may directly affect reverse transcriptase (RT) activity. Trace amounts of Mn(2+) potently inhibit Ty1 RT and HIV-1 RT in vitro when the preferred cation, Mg(2+), is present. Both Mn(2+) and Mg(2+) alone activate Ty1 RT cooperatively with Hill coefficients of 2, providing kinetic evidence for a dual divalent cation requirement at the RT active site. We propose that occupancy of the B site is the major determinant of catalytic activity and that Mn(2+) at this site greatly reduces catalytic activity.

Publication types

  • Comparative Study
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Binding Sites
  • Calcium-Transporting ATPases / genetics
  • Calcium-Transporting ATPases / metabolism*
  • Catalysis
  • Catalytic Domain
  • Cations / metabolism
  • DNA, Complementary / genetics
  • Enzyme Activation / drug effects
  • HIV Reverse Transcriptase / chemistry
  • HIV Reverse Transcriptase / drug effects*
  • HIV Reverse Transcriptase / metabolism
  • HIV-1 / drug effects
  • HIV-1 / enzymology
  • Ion Transport
  • Kinetics
  • Magnesium / pharmacology
  • Manganese / pharmacology*
  • Molecular Chaperones / genetics
  • Molecular Chaperones / metabolism*
  • RNA-Directed DNA Polymerase / chemistry
  • RNA-Directed DNA Polymerase / drug effects*
  • RNA-Directed DNA Polymerase / metabolism
  • Recombinant Fusion Proteins / metabolism
  • Retroelements / drug effects*
  • Reverse Transcriptase Inhibitors / pharmacology*
  • Saccharomyces cerevisiae / drug effects*
  • Saccharomyces cerevisiae / enzymology
  • Saccharomyces cerevisiae Proteins / genetics
  • Saccharomyces cerevisiae Proteins / metabolism*
  • Transcription, Genetic / drug effects*

Substances

  • Cations
  • DNA, Complementary
  • Molecular Chaperones
  • Recombinant Fusion Proteins
  • Retroelements
  • Reverse Transcriptase Inhibitors
  • SSC1 protein, S cerevisiae
  • Saccharomyces cerevisiae Proteins
  • Manganese
  • HIV Reverse Transcriptase
  • RNA-Directed DNA Polymerase
  • Calcium-Transporting ATPases
  • Magnesium