Mazo A M, Arkhipova I R, Cherkasova V A, Gorelova T V, Shuppe N G
Genetika. 1986 Mar;22(3):378-89.
In Drosophila melanogaster cultured cells, RNA reverse transcription intermediate forms connected with initiation of minus and plus DNA strand synthesis (minus and plus strong-stop DNA) are detected for mobile dispersed genetic elements MDG1, MDG3 and MDG4 (gypsy). A comparative analysis of intermediate forms has proved that mdg elements pass the same stages of reverse transcription as retroviruses, revealing a complete similarity between intermediate products. It has also been established that these three mdg elements possess a common mechanism of reverse transcription, despite their structural differences. The length of the minus strong-stop DNA, that gives the position of the RNA start site, coincides with the data obtained from SI nuclease analysis of transcription initiation. SI mapping has also revealed that mdg RNA carries a repeated sequence R on its ends, similar to retroviral RNA molecules, and that mdg LTRs have a U3-R-U5 structure analogous to that of proretroviral LTRs. Transcription of mdg1, mdg3 and mdg4 is initiated within or immediately after the same sequence TCAGTPy. Neither TATA box nor CAAT box can be found in their characteristic positions upstream of the 5' ends of mRNA.
在黑腹果蝇培养细胞中，对于移动分散遗传元件MDG1、MDG3和MDG4（吉普赛），检测到与负链和正链DNA合成起始相关的RNA逆转录中间形式（负链和正链强终止DNA）。对中间形式的比较分析证明，mdg元件经历与逆转录病毒相同的逆转录阶段，揭示了中间产物之间的完全相似性。还确定这三种mdg元件尽管结构不同，但具有共同的逆转录机制。给出RNA起始位点位置的负链强终止DNA的长度，与转录起始的SI核酸酶分析获得的数据一致。SI图谱还显示，mdg RNA在其末端携带一个重复序列R，类似于逆转录病毒RNA分子，并且mdg长末端重复序列具有类似于前病毒长末端重复序列的U3-R-U5结构。mdg1、mdg3和mdg4的转录在相同序列TCAGTPy内或之后立即起始。在mRNA 5'端上游的特征位置未发现TATA盒或CAAT盒。
