Paces V, Hostomský Z, Fucík V, Pivec L, Zadrazil S
Folia Biol (Praha). 1984;30 Spec No:52-64.
Morphologically identical phages PZA, PZE , phi 29, and phi 15 can be distinguished by the neutralization test with rabbit antisera and by host range specificity. Each member of this phage group contains 18 kb double-stranded linear DNA carrying proteins covalently attached to its 5' ends. Physical maps of their DNA constructed with the use of restriction endonucleases EcoRI, HpaI, HindIII, BspRI, and XbaI and DNA-DNA hybridization experiments show a closer relationship between phi 29 and PZE than between phi 29 and phi 15 or phi 29 and PZA. phi 15 is closer to PZA than to phi 29. This conclusion is supported by analysis of differential denaturation profiles of the phage DNAs. Sequencing of selected parts of phi 29 and PZA DNAs reveals 93% homology with a preference for synonymous base replacements (silent mutations) randomly distributed in the coding regions. Using promoter-probe plasmid pPV33 -H the region functioning as a promoter in E. coli was localized on the smallest EcoRI fragment of PZA and phi 29 DNAs. Comparison of the nucleotide sequence of this region with known promoters of B. subtilis shows extensive homologies with at least two types of promoters of different specificities, namely those recognized by factors sigma 28 of B. subtilis and sigma gp28 of phage SPO1 . These promoter-like regions overlap and the whole sequence is conserved in both phages.
形态上相同的噬菌体PZA、PZE、φ29和φ15可以通过兔抗血清中和试验和宿主范围特异性来区分。该噬菌体组的每个成员都含有18 kb的双链线性DNA，其5'端共价连接有蛋白质。利用限制性内切酶EcoRI、HpaI、HindIII、BspRI和XbaI构建的DNA物理图谱以及DNA-DNA杂交实验表明，φ29与PZE之间的关系比φ29与φ15或φ29与PZA之间的关系更密切。φ15与PZA的关系比与φ29的关系更密切。噬菌体DNA的差异变性图谱分析支持了这一结论。对φ29和PZA DNA的选定部分进行测序，发现它们有93%的同源性，且倾向于在编码区随机分布的同义碱基替换（沉默突变）。使用启动子探针质粒pPV33-H，在大肠杆菌中起启动子作用的区域定位于PZA和φ29 DNA的最小EcoRI片段上。将该区域的核苷酸序列与枯草芽孢杆菌已知启动子进行比较，发现与至少两种不同特异性的启动子有广泛的同源性，即枯草芽孢杆菌的σ28因子和噬菌体SPO1的σgp28因子识别的启动子。这些类启动子区域相互重叠，并且整个序列在两种噬菌体中都是保守的。
