Sekine Y, Ohtsubo E
Institute of Applied Microbiology, University of Tokyo, Japan.
Proc Natl Acad Sci U S A. 1989 Jun;86(12):4609-13. doi: 10.1073/pnas.86.12.4609.
Insertion sequence IS1 has two coding frames, insA and insB, which are essential for its transposition. Here, we show that a frameshifting event in the -1 direction from the 3' end region of the insA frame to an open reading frame (B' frame), extending from the 5' end of the insB frame, is involved in production of the InsA-B'-InsB fusion protein that has IS1 transposase activity. The frameshifting event is likely to have occurred at the sequence AAAAAC where the insA frame overlaps the B' frame. Interestingly, this sequence is also present in one of the two sequences identified in retroviruses as frameshift signals for production of transframe polyproteins from the overlapping genes gag-pro or gag-pro-pol.
插入序列IS1有两个编码框，insA和insB，这两个编码框对其转座至关重要。在此，我们表明，从insA框的3'端区域向-1方向的移码事件会转至一个开放阅读框（B'框），该开放阅读框从insB框的5'端延伸，这一移码事件参与了具有IS1转座酶活性的InsA-B'-InsB融合蛋白的产生。移码事件很可能发生在insA框与B'框重叠的AAAAAC序列处。有趣的是，该序列也存在于逆转录病毒中鉴定出的两个序列之一中，作为从重叠基因gag-pro或gag-pro-pol产生移码多聚蛋白的移码信号。
