期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：1982
卷号：79
期号：17
页码：5220-5224
DOI：10.1073/pnas.79.17.5220
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：Viroids are small "naked" infectious RNA molecules that are pathogens of higher plants. The potato spindle tuber viroid (PSTV) is composed of a covalently closed circular RNA molecule containing 359 ribonucleotides. The properties of PSTV were compared with those of the scrapie agent, which causes a degenerative neurological disease in animals. PSTV was inactivated by ribonuclease digestion, psoralen photoadduct formation, Zn2+ -catalyzed hydrolysis, and chemical modification with NH2OH. The scrapie agent resisted inactivation by these procedures, which modify nucleic acids. The scrapie agent was inactivated by proteinase K and trypsin digestion, chemical modification with diethylpyrocarbonate, and by exposure to phenol, NaDodSO4, KSCN, or urea. PSTV resisted inactivation by these procedures, which modify proteins. Earlier evidence suggested that the scrapie agent is smaller than PSTV. Its small size seems to preclude the presence of a genome coding for the protein(s) of a putative capsid. The properties of the scrapie agent distinguish it from both viroids and viruses and have prompted the introduction of the term "prion" to denote a small proteinaceous infectious particle that resists inactivation by procedures that modify nucleic acids.
