CK2调控早老细胞异染色质DNA损伤应答机制研究

发布时间：2018-02-22 20:39

本文关键词： 衰老 Lamin A CK2 HP1 DNA损伤　出处：《深圳大学》2017年硕士论文　论文类型：学位论文

【摘要】：衰老是一种生理功能的渐进性缺失的过程,在细胞水平表现为自我修复能力的减退和不可逆的生长停滞。其主要原因包括DNA损伤的累积、端粒的缩短和INK4a/ARF激活等。HGPS早老症是研究衰老机制的重要模型,Lamin基因的第11号外显子1824碱基位点C突变为T,导致lamin A的加工缺失50个氨基酸序列从而引发HGPS早老症。异染色质蛋白HP1(Heterochromatin Protein 1)是维持异染色质形成的重要组成部分,近年来研究发现HP1可以调控ATM-KAP-1介导的DNA损伤修复通路。CK2作为一种广泛分布于真核生物的保守丝氨酸/苏氨酸/酪氨酸蛋白激酶,调控细胞的信号转导、生存、衰老及凋亡。以往研究发现Zmpste24-缺陷型细胞在发生DNA损伤后HP1αT50磷酸化水平比野生型细胞明显偏低和延迟。并且利用si RNA干扰HP1α降低其表达水平后,Zmpste24-缺陷型细胞对DNA损伤反应的应答有所改善。本文在此基础上利用Zmpste24-缺陷早老小鼠模型为研究对象,探究在早老模型中蛋白激酶CK2调控HP1α影响DNA损伤修复过程,研究发现:1.HP1αT50位点的突变会影响异染色质对DNA损伤的应答;2.CK2是调控HP1αT50位点磷酸化的关键激酶;3.核纤层蛋白Lamin A与CK2存在相互作用,并介导其参与异染色质DNA损伤应答;4.在Zmpste24-缺陷型早老细胞中,CK2酶活性降低,导致DNA损伤堆积;5.小分子药物TBB抑制早老细胞CK2酶活性,导致细胞DNA损伤应答障碍,会促进早老细胞凋亡。总结以上实验结果,我们得出结论:1.lamin A-CK2α-HP1α通路参与早老细胞DNA损伤应答过程;2.抑制早老细胞CK2酶活性,早老细胞凋亡水平升高,细胞衰老分子标志物P16表达水平明显降低。因此,根据本论文的研究结果提示:抑制早老细胞CK2酶活性,会阻碍早老细胞中lamin A-CK2α-HP1α通路参与DNA损伤应答过程,导致细胞DNA损伤堆积,加速早老细胞凋亡,有利于清除衰老的细胞,达到抗衰老目的。
[Abstract]:Aging is a process of progressive loss of physiological function, which is characterized by a decline in self-repair and irreversible growth at the cellular level. The main causes include the accumulation of DNA damage. Telomere shortening and INK4a/ARF activation. HGPS-based early-aging syndrome is an important model for the study of aging mechanism. The 1824 base site C in exon 11 of the Lamin gene mutates to T, resulting in the deletion of 50 amino acid sequences in the processing of lamin A and the initiation of HGPS premature disease. Heterochromatin protein HP1(Heterochromatin Protein 1 is an important component of maintaining heterochromatin formation. In recent years, it has been found that HP1 can regulate DNA damage repair pathway mediated by ATM-KAP-1. CK2 is a conserved serine / threonine / tyrosine protein kinase widely distributed in eukaryotes, regulating cell signal transduction and survival. Senescence and apoptosis. Previous studies have found that the phosphorylation level of HP1 伪 T50 in Zmpste24- deficient cells after DNA damage is significantly lower and delayed than that of wild type cells, and that the expression level of HP1 伪 in Zmpste24- deficient cells is significantly lower than that in wild-type cells after HP1 伪 expression is reduced by si RNA. On the basis of this, the Zmpste24- deficient early aging mice model was used as the research object. To explore the effect of protein kinase CK2 on DNA damage and repair in the early aging model by regulating HP1 伪. It was found that the mutation at 1: 1 HP1 伪 T50 site affected the response of heterochromatin to DNA damage. CK2 was the key kinase to regulate the phosphorylation of HP1 伪 T50 site. The nuclear fiber laminin Lamin A interacted with CK2. In Zmpste24- deficient early aged cells, the activity of CK2 decreased, which led to the accumulation of DNA damage. The small molecular drug TBB inhibited the activity of CK2 enzyme in the early aged cells and led to the impairment of DNA damage in the cells. Conclusion: 1. Lamin A-CK2 伪 -HP1 伪 pathway plays an important role in the process of DNA damage response. 2. Inhibition of CK2 enzyme activity and increase of apoptosis level in early aging cells. The expression of P16, a molecular marker of cell senescence, was significantly decreased. Therefore, according to the results of this study, the inhibition of CK2 enzyme activity in the aged cells may hinder the lamin A-CK2 伪 -HP1 伪 pathway in the early aging cells to participate in the process of DNA damage response. It can cause DNA damage and accelerate the apoptosis of early aging cells, which is helpful to clear the aging cells and achieve the purpose of anti-aging.
【学位授予单位】：深圳大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：R339.38

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