Ratcliff S W, Luh J, Ganesan A T, Behrens B, Thompson R, Montenegro M A, Morelli G, Trautner T A
Mol Gen Genet. 1979 Jan 10;168(2):165-72. doi: 10.1007/BF00431442.
SPP1 DNA was cleaved by the restriction endonucleases, BglI, BglII, EcoRI, KpnI, SmaI, and SalI. The molecular weights of the DNA fragments obtained by single enzyme digestion or by consecutive digestion with two enzymes were determined by electron microscopic measurements of contour length and by gel electrophoresis. The major fragments from the six digests could be ordered to give a consistent restriction map of SPP1. The electropherograms of several digests indicated that certain fragments occurred in less than stoichiometric amounts or were heterogeneous in size. Such bands carried a major part of radioactivity, when SPP1 DNA was terminally labelled with P32 prior to degradation by restriction enzymes. These results, and studies of the effect of exonuclease III treatment on restriction enzyme patterns define the terminal restriction fragments. All data obtained support the conclusion drawn in the preceding paper (Morelli et al., 1978 b) that the SPP1 genome is terminally redundant and partially circularly permuted.
SPP1 DNA 被限制性内切酶 BglI、BglII、EcoRI、KpnI、SmaI 和 SalI 切割。通过单酶消化或两种酶连续消化获得的 DNA 片段的分子量，通过轮廓长度的电子显微镜测量和凝胶电泳来确定。六种消化产物的主要片段可以排序，以给出一致的 SPP1 限制性图谱。几种消化产物的电泳图表明，某些片段的出现量少于化学计量，或者大小不均一。当 SPP1 DNA 在被限制性酶降解之前用 P32 进行末端标记时，这些条带携带了大部分放射性。这些结果以及外切核酸酶 III 处理对限制性酶切图谱影响的研究确定了末端限制性片段。获得的所有数据都支持前一篇论文（莫雷利等人，1978 年 b）得出的结论，即 SPP1 基因组是末端冗余且部分环状排列的。
