Gu Y, Alder H, Nakamura T, Schichman S A, Prasad R, Canaani O, Saito H, Croce C M, Canaani E
Jefferson Cancer Institute, Jefferson Cancer Center, Jefferson Medical College of Thomas Jefferson University, Philadelphia, Pennsylvania 19107.
Cancer Res. 1994 May 1;54(9):2327-30.
DNA rearrangements caused by chromosome translocations between band 11q23 and various chromosomes can be detected by a single probe, B859, an 859-base pair complementary DNA fragment derived from the human ALL-1 gene. To try to understand why band 11q23 becomes a frequent target of the translocations, we have sequenced the entire breakpoint cluster region, a 8342-base pair BamHI genomic fragment delineated by B859. We found eight Alu repeats located within this region in the same orientation as the ALL-1 gene. We have also analyzed the sequences of the breakpoints in 10 patients with 6 different types of 11q23 aberration. In five patients the breaks coincided with Alu sequences on chromosome 11, but not on the partner chromosomes. Also, seven of the breaks occurred in the region delineated by exons 6 and 7, which is composed mainly of Alu sequences. In three patients topoisomerase II recognition site-like sequences, at different stringency levels, were identified at the breakpoints on chromosome 11. We conclude that while there is no specific sequence element present at all the breakpoints, the high density of Alu sequences in the breakpoint cluster region possibly makes the latter more prone to recombination events.
由11q23带与各种染色体之间的染色体易位引起的DNA重排，可用单一探针B859检测，该探针是一个源自人类ALL-1基因的859个碱基对的互补DNA片段。为了试图理解为何11q23带成为易位的常见靶点，我们对整个断点簇区域进行了测序，这是一个由B859划定的8342个碱基对的BamHI基因组片段。我们在该区域内发现了八个与ALL-1基因同向的Alu重复序列。我们还分析了10例患有6种不同类型11q23畸变患者的断点序列。在5例患者中，断点与11号染色体上的Alu序列相符，但与配对染色体上的不符。此外，7个断点发生在由外显子6和7划定的区域，该区域主要由Alu序列组成。在3例患者中，在11号染色体的断点处鉴定出不同严格程度的拓扑异构酶II识别位点样序列。我们得出结论，虽然并非所有断点处都存在特定的序列元件，但断点簇区域中Alu序列的高密度可能使该区域更容易发生重组事件。
