Telomere elongation through hTERT immortalization leads to chromosome repositioning in control cells and genomic instability in Hutchinson-Gilford progeria syndrome fibroblasts, expressing a novel SUN1 isoform
Telomere elongation through hTERT immortalization leads to chromosome repositioning in control cells and genomic instability in Hutchinson-Gilford progeria syndrome fibroblasts, expressing a novel SUN1 isoform
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DOI：
10.1002/gcc.22711
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发表时间：
2019-06-01
影响因子：
3.7
通讯作者：
Bridger, Joanna M.
中科院分区：
文献类型：
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作者：
Bikkul, Mehmet U.;Faragher, Richard G. A.;Bridger, Joanna M.
用人类端粒酶逆转录酶（hTERT）使原代细胞永生化是一种常见的做法，使原代细胞在实验室中得到广泛使用，因为它们避免了复制性衰老。研究细胞中外源表达的hTERT也为科学家提供了早期癌变和端粒行为的模型。控制和早衰疾病hutchinson - gilford早衰综合征（HGPS）原发性真皮成纤维细胞，有或没有经典的G608G突变，外源性hTERT已使其不朽。然而，令人惊讶的是，hTERT永生化不仅在疾病细胞中引起基因组重组，而且在正常对照细胞中也引起基因组重组，因此，在增殖成纤维细胞中，通常位于核外周的整个染色体区域在核内部错误定位。这包括对照成纤维细胞中的18号染色体和HGPS细胞中的18号和X号染色体，它们在物理上表达LINC复合物蛋白SUN1的同型体，这在以前只是理论上的。此外，这种HGPS细胞系也变得基因组不稳定，具有四倍体核型，这可能是由于新的SUN1亚型。长期使用hTERT抑制剂BIBR1532治疗能够减少永生化细胞的端粒长度，并导致这些错误定位的内部染色体位于核周围，如在活跃增殖细胞中评估的那样。综上所述，这些发现揭示了端粒延长导致染色体错位，这可以通过端粒重新缩短的药物治疗来恢复，并且一种新的SUN1亚型与延长的端粒结合导致基因组不稳定。因此，在解释来自htert永生化细胞系的基因组研究数据时应小心谨慎。
Immortalizing primary cells with human telomerase reverse transcriptase (hTERT) has been common practice to enable primary cells to be of extended use in the laboratory because they avoid replicative senescence. Studying exogenously expressed hTERT in cells also affords scientists models of early carcinogenesis and telomere behavior. Control and the premature ageing diseaseHutchinson-Gilford progeria syndrome (HGPS) primary dermal fibroblasts, with and without the classical G608G mutation have been immortalized with exogenous hTERT. However, hTERT immortalization surprisingly elicits genome reorganization not only in disease cells but also in the normal control cells, such that whole chromosome territories normally located at the nuclear periphery in proliferating fibroblasts become mislocalized in the nuclear interior. This includes chromosome 18 in the control fibroblasts and both chromosomes 18 and X in HGPS cells, which physically express an isoform of the LINC complex protein SUN1 that has previously only been theoretical. Additionally, this HGPS cell line has also become genomically unstable and has a tetraploid karyotype, which could be due to the novel SUN1 isoform. Long-term treatment with the hTERT inhibitor BIBR1532 enabled the reduction of telomere length in the immortalized cells and resulted that these mislocalized internal chromosomes to be located at the nuclear periphery, as assessed in actively proliferating cells. Taken together, these findings reveal that elongated telomeres lead to dramatic chromosome mislocalization, which can be restored with a drug treatment that results in telomere reshortening and that a novel SUN1 isoform combined with elongated telomeres leads to genomic instability. Thus, care should be taken when interpreting data from genomic studies in hTERT-immortalized cell lines.