Hartley N M, Murphy G O, Bruton C J, Chater K F
Cambridge Laboratory, John Innes Centre, Norwich, UK.
Gene. 1994 Sep 15;147(1):29-40. doi: 10.1016/0378-1119(94)90035-3.
The temperate phage phi C31 is the most studied bacteriophage infecting Streptomyces spp., and has been used to develop an extensive and widely used series of cloning vectors. The sequence of 10 kb of phi C31 DNA containing most or all of the essential early genes was determined. Among the ORFs, 14 (perhaps 15) appear to be protein-coding, and these have been designated ORF1 to ORF14 and ORFX. Previously mapped transcripts appear to initiate upstream from ORFs 1, 8, 11 and 12, and within ORF3 and ORF12, in each case close to one example of the unusual ('21-mer') sequences that appear to serve as a recognition site for RNA polymerase early in the phi C31 lytic cycle [Ingham et al., Mol. Microbiol. 9 (1993) 1267-1274]. Further copies of the 21-mer are upstream from ORF2 and ORF13. There are four recognisable examples of a conserved inverted repeat sequence motif (CIR) thought to bind phi C31 repressor [Smith and Owen, Mol. Microbiol. 5 (1991) 2833-2844]. Only one CIR is closely associated with a 21-mer sequence, though three are located between known transcription units. Of all 14 ORFs, only one (ORF11) would encode a protein unmistakably resembling other known proteins; its product appears to be a DNA polymerase. Strikingly, two codons, TTA (Leu) and AGG (Arg), are absent from the 14 ORFs.
温和噬菌体phi C31是研究最多的感染链霉菌属的噬菌体，已被用于开发一系列广泛且被广泛使用的克隆载体。测定了包含大部分或所有必需早期基因的10 kb phi C31 DNA序列。在这些开放阅读框（ORF）中，14个（可能15个）似乎是蛋白质编码的，这些被命名为ORF1至ORF14以及ORFX。先前绘制的转录本似乎在ORF1、8、11和12的上游起始，以及在ORF3和ORF12内起始，每种情况都靠近一个不寻常的（“21聚体”）序列的例子，这些序列似乎在phi C31裂解周期早期作为RNA聚合酶的识别位点[英厄姆等人，《分子微生物学》9（1993年）1267 - 1274]。21聚体的其他拷贝在ORF2和ORF13的上游。有四个可识别的保守反向重复序列基序（CIR）的例子，被认为与phi C31阻遏物结合[史密斯和欧文，《分子微生物学》5（1991年）2833 - 2844]。只有一个CIR与一个21聚体序列紧密相关，尽管有三个位于已知转录单元之间。在所有14个ORF中，只有一个（ORF11）会编码一种明显类似于其他已知蛋白质的蛋白质；其产物似乎是一种DNA聚合酶。引人注目的是，14个ORF中没有两个密码子，即TTA（亮氨酸）和AGG（精氨酸）。
