Methylation silencing and reactivation of exogenous genes in lentivirus-mediated transgenic mice
Methylation silencing and reactivation of exogenous genes in lentivirus-mediated transgenic mice
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DOI：
10.1007/s11248-020-00224-9
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发表时间：
2021-01
影响因子：
3
通讯作者：
Jinkun Wen;Jinni Wu;Tianqi Cao;Shengyao Zhi;Yuxi Chen;L. Aagaard;Peilin Zhen;Yanming Huang;Jianxin Zhong;Junjiu Huang
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作者：
Jinkun Wen;Jinni Wu;Tianqi Cao;Shengyao Zhi;Yuxi Chen;L. Aagaard;Peilin Zhen;Yanming Huang;Jianxin Zhong;Junjiu Huang
利用它们将其基因组整合到宿主基因组中的能力，慢病毒已被用于在生物医学研究中快速产生转基因小鼠。在大多数情况下，由慢病毒载体递送的转基因在小鼠中抵抗由表观遗传修饰介导的沉默。然而，一些研究表明甲基化导致小鼠中转基因表达降低。因此，关于甲基化诱导的小鼠慢病毒转导转基因沉默存在相互矛盾的证据。在这项研究中，我们提出的证据表明，在慢病毒转导产生的转基因小鼠模型的肝脏中，人类TTR转基因被DNA甲基化沉默。在繁殖过程中，转基因上的甲基化密度增加，并且转基因的表达在F2代小鼠中完全沉默。有趣的是，5-氮杂胞苷（5-AzaC），一种甲基转移酶抑制剂，有效地重新激活了新生小鼠中沉默的基因，这些小鼠的肝细胞正在积极增殖，并在发育过程中导致稳定的转基因表达。然而，5-AzaC没有拯救肝脏转基因表达时，给药到成年小鼠。此外，给定剂量的5-AzaC在新生小鼠中具有低发育毒性。总之，我们证明了慢病毒转导产生的小鼠模型肝脏中外源基因的甲基化诱导沉默，并表明沉默的转基因可以通过5-AzaC处理安全有效地重新激活，提供了一种替代方法，以获得在慢病毒转导产生的转基因小鼠中外源基因甲基化的情况下具有稳定转基因表达的后代。
Taking advantage of their ability to integrate their genomes into the host genome, lentiviruses have been used to rapidly produce transgenic mice in biomedical research. In most cases, transgenes delivered by lentiviral vectors have resisted silencing mediated by epigenetic modifications in mice. However, some studies revealed that methylation caused decreased transgene expression in mice. Therefore, there is conflicting evidence regarding the methylation-induced silencing of transgenes delivered by lentiviral transduction in mice. In this study, we present evidence that the humanTTRtransgene was silenced by DNA methylation in the liver of a transgenic mouse model generated by lentiviral transduction. The density of methylation on the transgene was increased during reproduction, and the expression of the transgene was completely silenced in mice of the F2 generation. Interestingly, 5-azacytidine (5-AzaC), a methyltransferase inhibitor, potently reactivated the silenced genes in neonatal mice whose hepatocytes were actively proliferating and led to stable transgene expression during development. However, 5-AzaC did not rescue liver transgene expression when administered to adult mice. Moreover, 5-AzaC at the given dose had low developmental toxicity in the newborn mice. In summary, we demonstrate the methylation-induced silencing of an exogenous gene in the liver of a mouse model generated by lentiviral transduction and show that the silenced transgene can be safely and efficiently reactivated by 5-AzaC treatment, providing an alternative way to obtain progeny with stable transgene expression in the case of the methylation of exogenous genes in transgenic mice generated by lentiviral transduction.