Deletions and rearrangements of DNA sequences within the genome of human cells result in mutations associated with human disease. We have developed a selection system involving a neo gene containing a DNA sequence inserted into the NcoI site that can be used to quantitatively assay deletion of this sequence from the chromosome. The spontaneous deletion from the neo gene of a 122 bp inverted repeat occurred at a rate of 2.1 x 10(-8) to <3.1 x 10(-9) revertants/cell/generation in three different cell lines. Deletion of the 122 bp inverted repeat occurred between 6 bp flanking direct repeats. Spontaneous deletion of a 122 bp non-palindromic DNA sequence flanked by direct repeats was not observed, indicating a rate of deletion of <3.1 x 10(-9) revertants/cell/generation. This result demonstrates that a 122 bp inverted repeat can exhibit a low level of instability in some locations in the chromosome of a human cell line.
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机译：人类细胞基因组中DNA序列的缺失和重排导致与人类疾病相关的突变。我们已经开发了一种选择系统，该系统涉及一个新基因，该新基因包含一个插入NcoI位点的DNA序列，可用于定量测定该序列从染色体中的缺失。在三种不同的细胞系中，neo基因自发缺失了122 bp的反向重复序列，其回复率/细胞/世代的发生率为2.1 x 10（-8）至<3.1 x 10（-9）。 122bp反向重复序列的缺失发生在6bp侧翼直接重复序列之间。没有观察到122 bp的非回文DNA序列被直接重复序列侧翼的自发删除，表明删除率<3.1 x 10（-9）回复株/细胞/世代。该结果表明122bp的反向重复序列可以在人细胞系的染色体的某些位置表现出低水平的不稳定性。
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