Mitra S W, Goff S, Gilboa E, Baltimore D
Proc Natl Acad Sci U S A. 1979 Sep;76(9):4355-9. doi: 10.1073/pnas.76.9.4355.
A discrete, 600-nucleotide-long plus-strand DNA has been identified among the products of reverse transcription by virions of Moloney murine leukemia virus. Its polarity was shown by hybridization to minus-strand DNA. It appears to be copied from the right end of minus-strand DNA because (i) its restriction endonuclease cleavage pattern corresponds to the redundant 600-base segment found at either end of the ultimate double-stranded reverse transcription products, (ii) its synthesis is actinomycin D sensitive, and (iii) its synthesis begins during the first hour of a reverse transcription reaction when only the right-hand end of minus-strand DNA is available as template. We therefore call this DNA plus-strong-stop DNA by analogy with the minus-strong-stop DNA copied from the left end of the viral RNA. Both strong-stop DNAs are made early during in vitro reactions and decline in concentration later, consistent with postulated roles as initiators of long minus- and plus-strand DNA. Unlike minus-strong-stop DNA, plus-strong-stop DNA remains as a double-stranded nucleic acid after its synthesis, as shown by S1 nuclease resistance. A primer to initiate plus-strong-stop DNA synthesis has not been identified; the product found thus far has no detectable RNA attached to it.
在莫洛尼鼠白血病病毒粒子的逆转录产物中，已鉴定出一段离散的、长度为600个核苷酸的正链DNA。通过与负链DNA杂交确定了其极性。它似乎是从负链DNA的右端复制而来，因为：（i）其限制性内切酶切割模式与在最终双链逆转录产物两端发现的冗余600碱基片段相对应；（ii）其合成对放线菌素D敏感；（iii）其合成在逆转录反应的第一个小时内开始，此时只有负链DNA的右端可作为模板。因此，我们将这种DNA称为正链强终止DNA，以类比从病毒RNA左端复制的负链强终止DNA。两种强终止DNA都是在体外反应早期产生的，随后浓度下降，这与它们作为长负链和正链DNA起始物的假定作用一致。与负链强终止DNA不同，正链强终止DNA在合成后仍作为双链核酸存在，这通过S1核酸酶抗性得以证明。尚未鉴定出启动正链强终止DNA合成的引物；到目前为止发现的产物上没有可检测到的RNA附着。
