Driver A, Lacey S F, Cullingford T E, Mitchelson A, O'Hare K
Department of Biochemistry, Imperial College of Science, Technology and Medicine, London, UK.
Mol Gen Genet. 1989 Dec;220(1):49-52. doi: 10.1007/BF00260854.
DNA sequences from two spontaneous mutations of Drosophila melanogaster associated with insertion of a Doc transposable element have been cloned. In white-one, the element is inserted in the white locus close to where transcription initiates. In a lethal allele of suppressor of forked, su(f)S2, the element is inserted within the transcription unit in the protein coding region. Four other Doc elements have been cloned from a wild-type strain. Doc is a member of the class of transposable elements known as retroposons, which includes the D. melanogaster F, G, Jockey, and I elements. There is no sequence homology between the ends of the Doc element. The 3' or right end terminates with a polyadenylation signal sequence followed by a stretch of oligo-A. The length of the oligo-A varies between elements, and a duplication of variable size is found as a direct repeat flanking inserted Doc elements. Members of the family are conserved at the 3' end, but may be truncated at the 5' or left end. These structural features suggest a mechanism of transposition via an RNA intermediate.
已克隆出与Doc转座元件插入相关的黑腹果蝇两个自发突变的DNA序列。在white-one中，该元件插入到靠近转录起始位点的白色基因座中。在叉状抑制因子的一个致死等位基因su(f)S2中，该元件插入到蛋白质编码区的转录单元内。已从一个野生型菌株中克隆出另外四个Doc元件。Doc是被称为反转录转座子的转座元件类别的成员，其中包括黑腹果蝇的F、G、Jockey和I元件。Doc元件的末端之间没有序列同源性。3'端或右端以多聚腺苷酸化信号序列结尾，随后是一段寡聚A。寡聚A的长度在不同元件之间有所变化，并且发现一个大小可变的重复序列作为插入的Doc元件两侧的直接重复序列。该家族成员在3'端是保守的，但在5'端或左端可能被截断。这些结构特征提示了一种通过RNA中间体进行转座的机制。
