Wu M, Manor H, Davidson N
J Virol. 1979 Oct;32(1):334-8. doi: 10.1128/JVI.32.1.334-338.1979.
Three reproducible secondary-structure features were observed on single strands of polyoma virus DNA mounted for electron microscopy by the T4 gene 32 protein technique: (i) a hairpin fold-back extending from 92.9 +/- 0.8 to 95.0 +/- 0.7 map units; (ii) a small loop extending from 63.2 +/- 3.1 to 68.5 +/- 2.8 map units; and (iii) a big loop extending from 51.9 +/- 2.3 to 68.9 +/- 2.1 map units. Both loops are bounded by inverted repeat stems of length 40 +/- 20 base pairs. The stem sequences around 68.5 and 68.9 of the large and small loops overlap, either partially or completely. Several lines of evidence indicate that the inverted repeat stems of the two secondary-structure loops lie in the regions of polyoma virus DNA flanking and probably very close to the sequences that are spliced out in the formation of the late 16S and 18S messages, whereas the hairpin fold-back appears to map at a splicing point of an early message. These structures may therefore be important for the processing of the primary transcripts to form the early and late messages.
通过T4基因32蛋白技术制备用于电子显微镜观察的多瘤病毒DNA单链上，观察到三个可重复的二级结构特征：（i）一个发夹回折结构，从92.9±0.8至95.0±0.7图距单位延伸；（ii）一个小环，从63.2±3.1至68.5±2.8图距单位延伸；以及（iii）一个大环，从51.9±2.3至68.9±2.1图距单位延伸。两个环均由长度为40±20个碱基对的反向重复茎环界定。大小环68.5和68.9周围的茎环序列部分或完全重叠。几条证据表明，两个二级结构环的反向重复茎环位于多瘤病毒DNA侧翼区域，可能非常接近在晚期16S和18S信使形成过程中被剪接掉的序列，而发夹回折结构似乎位于早期信使的一个剪接位点处。因此，这些结构可能对初级转录本加工形成早期和晚期信使很重要。
