Adenine depurination and inactivation of plant ribosomes by an antiviral protein of Mirabilis jalapa (MAP).
Mirabilis antiviral protein (MAP) is a single-chain ribosome-inactivating protein (RIP) isolated from Mirabilis jalapa L. It depurinates the 28S-like rRNAs of prokaryotes and eukaryotes. A specific modification in the 25S rRNA of M. jalapa was found to occur during isolation of ribosomes by polyacrylamide/agarose composite gel electrophoresis. Primer extension analysis revealed the modification site to be at the adenine residue corresponding to A4324 in rat 28S rRNA. The amount of endogenous MAP seemed to be sufficient to inactivate most of the homologous ribosomes. The adenine of wheat ribosomes was also found to be removed to some extent by an endogenous RIP (tritin). However, the amount of endogenous tritin seemed to be insufficient for quantitative depurination of the homologous ribosomes. Endogenous MAP could shut down the protein synthesis of its own cells when it spreads into the cytoplasm through breaks of the cells. Therefore, we speculate that MAP is a defensive agent to induce viral resistance through the suicide of its own cells.
Kataoka
J
J
Life Science Research Laboratory, Japan Tobacco Inc., Kanagawa.
Habuka
N
N
Miyano
M
M
Masuta
C
C
Koiwai
A
A
D000225:Adenine / Q000737:chemistry; D000998:Antiviral Agents; D001483:Base Sequence; D016384:Consensus Sequence; D004247:DNA / Q000235:genetics; D008969:Molecular Sequence Data; D009699:N-Glycosyl Hydrolases / Q000378:metabolism*; D010940:Plant Proteins / Q000378:metabolism*; D010947:Plants, Toxic; D016133:Polymerase Chain Reaction; D012335:RNA, Ribosomal / Q000737:chemistry / Q000378:metabolism*; D054788:Ribosome Inactivating Proteins; D054789:Ribosome Inactivating Proteins, Type 1; D012270:Ribosomes / Q000737:chemistry / Q000378:metabolism*; D014026:Nicotiana / Q000737:chemistry
D000998:Antiviral Agents; D010940:Plant Proteins; D012335:RNA, Ribosomal; C065096:RNA, ribosomal, 26S; D054789:Ribosome Inactivating Proteins, Type 1; D004247:DNA; D009699:N-Glycosyl Hydrolases; C059351:MAP protein, Mirabilis jalapa; D054788:Ribosome Inactivating Proteins; D000225:Adenine