Department of Chemistry, Graduate School of Science, Tokyo Metropolitan University, Minamiosawa 1-1, Hachioji-shi, Tokyo, 192-0397, Japan.
Sci Rep. 2021 Sep 10;11(1):18054. doi: 10.1038/s41598-021-97580-1.
A trisomy is a type of aneuploidy characterised by an additional chromosome. The additional chromosome theoretically accepts any kind of changes since it is not necessary for cellular proliferation. This advantage led us to apply two chromosome manipulation methods to autosomal trisomy in chicken DT40 cells. We first corrected chromosome 2 trisomy to disomy by employing counter-selection markers. Upon construction of cells carrying markers targeted in one of the trisomic chromosome 2s, cells that have lost markers integrated in chromosome 2 were subsequently selected. The loss of one of the chromosome 2s had little impacts on the proliferative capacity, indicating unsubstantial role of the additional chromosome 2 in DT40 cells. We next tested large-scale truncations of chromosome 2 to make a mini-chromosome for the assessment of chromosome stability by introducing telomere repeat sequences to delete most of p-arm or q-arm of chromosome 2. The obtained cell lines had 0.7 Mb mini-chromosome, and approximately 0.2% of mini-chromosome was lost per cell division in wild-type background while the rate of chromosome loss was significantly increased by the depletion of DDX11, a cohesin regulatory protein. Collectively, our findings propose that trisomic chromosomes are good targets to make unique artificial chromosomes.
三体是一种非整倍体，其特征是额外的染色体。由于额外的染色体对于细胞增殖不是必需的，因此它可以接受任何类型的变化。这个优势促使我们在鸡 DT40 细胞中应用两种染色体操作方法来处理常染色体三体。我们首先通过使用反选择标记来纠正 2 号染色体三体至二倍体。在构建携带靶向 2 号三体中一条染色体上标记的细胞后，随后选择丢失了整合在染色体 2 上的标记的细胞。丢失其中一条染色体 2 对增殖能力的影响很小，表明额外的染色体 2 在 DT40 细胞中的作用不大。接下来，我们测试了大规模截短染色体 2，通过引入端粒重复序列来删除染色体 2 的大部分 p 臂或 q 臂，从而制作迷你染色体，以评估染色体稳定性。获得的细胞系具有 0.7 Mb 的迷你染色体，在野生型背景下，每个细胞分裂大约有 0.2%的迷你染色体丢失，而当耗尽一个黏合蛋白调节蛋白 DDX11 时，染色体丢失的速度会显著增加。总的来说，我们的发现表明，三体染色体是制作独特人工染色体的良好目标。
