Kramer P R, Stringer J R, Sinden R R
Department of Biochemistry and Biophysics, Texas A&M University, Houston 77030-3303, USA.
Nucleic Acids Res. 1996 Nov 1;24(21):4234-41. doi: 10.1093/nar/24.21.4234.
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.
人类细胞基因组内DNA序列的缺失和重排会导致与人类疾病相关的突变。我们开发了一种选择系统，该系统涉及一个新霉素基因（neo基因），其NcoI位点插入了一段DNA序列，可用于定量检测该序列从染色体上的缺失情况。在三种不同的细胞系中，122 bp反向重复序列从neo基因上自发缺失的频率为2.1×10⁻⁸至<3.1×10⁻⁹回复子/细胞/代。122 bp反向重复序列的缺失发生在6 bp侧翼同向重复序列之间。未观察到由同向重复序列侧翼的122 bp非回文DNA序列的自发缺失，这表明缺失频率<3.1×10⁻⁹回复子/细胞/代。这一结果表明，122 bp反向重复序列在人类细胞系染色体的某些位置可能表现出低水平的不稳定性。
