Ku protein levels, localization and association to replication origins in different stages of breast tumor progression.
Ku protein levels, localization and association to replication origins in different stages of breast tumor progression.
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DOI：
10.7150/jca.6289
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发表时间：
2013
影响因子：
3.9
通讯作者：
Zannis-Hadjopoulos M
中科院分区：
文献类型：
--
作者：
Abdelbaqi K;Di Paola D;Rampakakis E;Zannis-Hadjopoulos M
人类DNA复制的起源是基因组内的特定序列，DNA复制由此开始。一组被称为预复制（pre-RC）复合体的精选蛋白质，在其形成中，Ku蛋白（Ku70/Ku86）被证明发挥作用，结合复制起点启动DNA复制。在这项研究中，我们研究了Ku在乳腺肿瘤发生和肿瘤进展中的作用，发现Ku蛋白在人类乳腺转移（MCF10AC1a）细胞中的表达水平在染色质部分高于增生（MCF10AT）和正常（MCF10A）人类乳腺细胞，但在细胞核和细胞质部分保持不变。相比之下，在人肠细胞中，Ku的表达水平在所有细胞组分中相对恒定。新生DNA丰度和Ku70/86的染色质关联表明，MCF10AC1a的c-myc起源活性分别比MCF10AT和MCF10A高2.5 ~ 5倍，并且Ku在MCF10AC1a中与c-myc起源的结合更丰富，分别比MCF10AT和MCF10A高约1.5 ~ 4.2倍。相比之下，在所有细胞系中都发现了相似的新生DNA丰度和染色质关联，这些DNA丰度和染色质关联与构成型活跃的内护层蛋白B2基因有关。对三种细胞类型的核提取物（NEs）进行的电泳迁移分析（EMSAs）显示，c-myc和lamin B2起源上都存在蛋白质- dna复制复合物，但c-myc起源的结合活性从正常细胞到转化细胞再到癌细胞都有所增加，而lamin B2起源的结合活性则没有这种差异。总的来说，结果表明，Ku染色质关联的增加，超过野生型水平，改变了与肿瘤发生有关的细胞过程。
Human origins of DNA replication are specific sequences within the genome whereby DNA replication is initiated. A select group of proteins, known as the pre-replication (pre-RC) complex, in whose formation the Ku protein (Ku70/Ku86) was shown to play a role, bind to replication origins to initiate DNA replication. In this study, we have examined the involvement of Ku in breast tumorigenesis and tumor progression and found that the Ku protein expression levels in human breast metastatic (MCF10AC1a) cells were higher in the chromatin fraction compared to hyperplastic (MCF10AT) and normal (MCF10A) human breast cells, but remained constant in both the nuclear and cytoplasmic fractions. In contrast, in human intestinal cells, the Ku expression level was relatively constant for all cell fractions. Nascent DNA abundance and chromatin association of Ku70/86 revealed that the c-myc origin activity in MCF10AC1a is 2.5 to 5-fold higher than in MCF10AT and MCF10A, respectively, and Ku was bound to the c-myc origin more abundantly in MCF10AC1a, by approximately 1.5 to 4.2-fold higher than in MCF10AT and MCF10A, respectively. In contrast, similar nascent DNA abundance and chromatin association was found for all cell lines for the lamin B2 origin, associated with the constitutively active housekeeping lamin B2 gene. Electrophoretic mobility shift assays (EMSAs) performed on the nuclear extracts (NEs) of the three cell types revealed the presence of protein-DNA replication complexes on both the c-myc and lamin B2 origins, but an increase in binding activity was observed from normal, to transformed, to cancer cells for the c-myc origin, whereas no such difference was seen for the lamin B2 origin. Overall, the results suggest that increased Ku chromatin association, beyond wild type levels, alters cellular processes, which have been implicated in tumorigenesis.
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影响因子：
14.9
作者：
Di Paola D;Rampakakis E;Chan MK;Arvanitis DN;Zannis-Hadjopoulos M
通讯作者：
Zannis-Hadjopoulos M
影响因子：
11.4
作者：
Klein, A;Miera, O;Schriever, F
通讯作者：
Schriever, F
影响因子：
10.5
作者：
KUHN, A;GOTTLIEB, TM;GRUMMT, I
通讯作者：
GRUMMT, I
DOI：
10.1073/pnas.95.2.525
发表时间：
1998-01-20
影响因子：
11.1
作者：
Hammarsten, O;Chu, G
通讯作者：
Chu, G
影响因子：
4.8
作者：
Koike, M;Shiomi, T;Koike, A
通讯作者：
Koike, A