Garon C F, Barbosa E, Moss B
Proc Natl Acad Sci U S A. 1978 Oct;75(10):4863-7. doi: 10.1073/pnas.75.10.4863.
An inverted terminal repetition was observed in DNA molecules extracted from vaccinia virus. The repeated sequence was visualized by (i) nicking the hairpin loops present of the ends of vaccinia virus DNA, (ii) separating the strands of DNA by alkali denaturation, (iii) allowing the single strands to self-anneal, and (iv) examining the DNA with an electron microscope. Single-stranded circular molecules, each of which contained a duplex projection (3.54 +/- 0.12 micron) representing the terminal repetition, readily formed. Similar size projections were also seen in heteroduplex structures formed by crosshybridization of the separated strands of the two terminal HindIII restriction fragments. Based on contour length measurements and the electrophoretic mobility of the isolated inverted terminal repetition, a molecular weight of approximately 6.9 X 10(6), equivalent to about 10,500 nucleotide base pairs, was estimated. Evidence was obtained from DNA-RNA hybridization studies that the terminal repetition is transcribed.
在从痘苗病毒中提取的DNA分子中观察到反向末端重复序列。通过以下步骤使重复序列可视化：（i）切开痘苗病毒DNA末端存在的发夹环；（ii）通过碱变性分离DNA链；（iii）使单链自我退火；（iv）用电子显微镜检查DNA。容易形成单链环状分子，每个分子都包含一个代表末端重复序列的双链突起（3.54±0.12微米）。在由两个末端HindIII限制性片段的分离链交叉杂交形成的异源双链结构中也观察到类似大小的突起。根据轮廓长度测量和分离的反向末端重复序列的电泳迁移率，估计分子量约为6.9×10⁶，相当于约10,500个核苷酸碱基对。DNA-RNA杂交研究获得的证据表明末端重复序列被转录。
