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：1973
卷号：70
期号：2
页码：466-470
DOI：10.1073/pnas.70.2.466
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：Purified preparations of RNA-dependent DNA polymerase isolated from avain myeloblastosis virus contain RNase H activity. Labeled ribohomopolymers are degraded in the presence of their complementary deoxyribopolymer, except [3H]poly(U){middle dot}poly(dA). The degradation products formed from [3H]poly(A){middle dot}poly(dT) were identified as oligonucleotides containing 3'-hydroxyl and 5'-phosphate termini, while AMP was not detected. The nuclease has been characterized as a processive exonuclease that requires ends of poly(A) chains for activity. Exonucleolytic attack occurs in both 5' to 3' and 3' to 5' directions. RNase H has also been purified from E. coli. This nuclease degrades all homoribopolymers tested in the presence of their complementary deoxyribopolymers to yield oligonucleotides with 5'-phosphate and 3'-hydroxyl termini. E. coli RNase H has been characterized as an endonuclease.
关键词：RNA-dependent DNA polymerase ; processive exonuclease ; E. coli endonuclease
