Function of MDC1/53BP1 sensor chaperone in radiation-induced chromatin repair

MDC1/53BP1传感器伴侣在辐射诱导染色质修复中的功能

• 批准号: 17310037
• 负责人: SUZUKI Keiji
• 金额: $ 6.78万
• 依托单位: Nagasaki University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B)
• 财政年份: 2005
• 资助国家: 日本
• 起止时间: 2005 至 2006
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-17310037/
• 关键词: ionizing radiation; chromosome; phosphorylation; histone; MDC1; 53BP1; ヒストンH2AX

The purpose of this study is to clarify the role of MDC1/53BP1 sensor chaperone on detection of chromatin damage and repair. In this study, a method by which phosphorylated histone H2AX foci and MDC1/53BP1 sensor chaperone foci can be detected was established.After X-irradiation, chromosome aberrations were induced. Immediately after irradiation, most of the chromosome aberration were chromatid-type, in contrast those detected 20 hours after irradiation were chromosome-type. the foci of phosphorylated histone H2AX were colocalized with chromatid-type aberrations immediately after irradiation, whereas the foci were colocalized with chromosome-type aberrations 20 hours after irradiation. These results indicate that the foci could persist or chromosomes without detectable breaks. It suggests that DNA damage checkpoint also senses chromatin damage, which is generated by mis-rejoining DNA double strand breaks.Furthermore, to know the function of MDC1/53BP1 sensor chaperone in the initial process of DNA/chromatin damage recognition, normal human cells harboring EGFP-53BP1 gene was established. Within 15 minutes after irradiation, EGFP-53BP1 foci were detected as tiny foci, but they grew thereafter, and 30 to 60 minutes after irradiation, they formed large foci, whose diameter was over 2 micrometer. Moreover, an inhibitor for ATM, KU55933, efficiently suppressed the foci of MDC1/53BP1 sensor chaperone. It clearly indicates that MDC1/53BP1 sensor chaperone foci formation is dependent on the ATM function.

本研究的目的是阐明MDC1/53BP1传感器伴侣在检测染色质损伤和修复中的作用。本研究建立了磷酸化组蛋白H2AX位点和MDC1/53BP1传感器伴侣蛋白位点的检测方法。x射线照射后，染色体发生畸变。照射后立即检测到的染色体畸变多为染色单体型，照射后20小时检测到的染色体畸变多为染色体型。磷酸化组蛋白H2AX在照射后立即与染色单体型畸变共定位，而在照射后20小时与染色体型畸变共定位。这些结果表明，病灶可以在染色体中持续存在而没有可检测到的断裂。这表明DNA损伤检查点也能感知染色质损伤，这是由DNA双链断裂错误重新连接产生的。此外，为了了解MDC1/53BP1传感器伴侣在DNA/染色质损伤识别初始过程中的功能，我们建立了携带EGFP-53BP1基因的正常人细胞。辐照后15分钟内检测到EGFP-53BP1病灶为小病灶，此后逐渐增大，辐照后30 ~ 60分钟形成大病灶，其直径超过2微米。此外，ATM抑制剂KU55933有效地抑制了MDC1/53BP1传感器伴侣蛋白的焦点。这清楚地表明MDC1/53BP1传感器伴侣焦点的形成依赖于ATM功能。

项目成果

Phosphorylated histone H2AX foci persists on rejoined mitotic chromosomes in normal human diploid cells exposed to ionizing radiation.

在暴露于电离辐射的正常人二倍体细胞中，磷酸化组蛋白 H2AX 焦点持续存在于重新连接的有丝分裂染色体上。

• 发表时间: 2006
• 期刊: Radiation Research 165
• 作者: Masatoshi Suzuki;et al.
• 通讯作者: et al.

Delayed activation of DNA damage checkpoint and radiation-induced genomic instability.

DNA 损伤检查点的延迟激活和辐射引起的基因组不稳定。

• 发表时间: 2006
• 期刊: Mutation Research 597
• 作者: Keiji Suzuki;et al.
• 通讯作者: et al.

Qualitative and quantitative analysis of phosphorylated ATM foci induced by low-dose ionizing radjation.

低剂量电离辐射诱导的磷酸化 ATM 病灶的定性和定量分析。

• 发表时间: 2006
• 期刊: Radiat.Res. 165・5
• 作者: Masatoshi Suzuki;et al.;Keiji Suzuki
• 通讯作者: Keiji Suzuki

Non-specific detection of the centrosomes by antibodies recognizing phosphorylated ATM at serine 1981.

通过识别丝氨酸磷酸化 ATM 的抗体对中心体进行非特异性检测 1981。

• 发表时间: 2006
• 期刊: Cell cycle 5・9
• 作者: Yoshida;Y.;Shimizu;A.;Baba,D.;Yoshida;N.;Inoue;Y.;Katayama;Keiji Suzuki;Keiji Suzuki
• 通讯作者: Keiji Suzuki

Abnormal stability of wild-type p53 protein in a human lung carcinoma cell line.

人肺癌细胞系中野生型 p53 蛋白的异常稳定性。

• 发表时间: 2005
• 期刊: Biochem. Biophys. Res. Commun. 330・2
• 作者: Masatoshi Suzuki;et al.;Keiji Suzuki;Keiji Suzuki;Masatoshi Suzuki;Nobuyuki Hamada;Motohiro Yamauchi
• 通讯作者: Motohiro Yamauchi