Molecular cloning and sequence analysis of the promoter region of mouse cyclin D1 gene: implication in phorbol ester-induced tumour promotion
Molecular cloning and sequence analysis of the promoter region of mouse cyclin D1 gene: implication in phorbol ester-induced tumour promotion
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DOI：
10.1046/j.1365-2184.2000.00176.x
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发表时间：
2000-06-01
影响因子：
8.5
通讯作者：
Eto, I
中科院分区：
文献类型：
--
作者：
Eto, I
Cyclin D1是一种细胞周期调节蛋白，作为生长因子传感器，将细胞外信号与细胞周期机制整合，特别是在细胞周期的G1期。先前对促进敏感的JB6小鼠表皮细胞（多阶段癌变促进阶段的体外模型）的研究表明，在不依赖锚定培养条件下维持的这些细胞中，12- o - tetradecanoylphorpol -13-acetate （TP，A）存在（但不存在）时，cyclin D1的表达受到刺激。本研究为探究这一现象的分子基础，对小鼠cyclin D1基因启动子区域进行了克隆和测序（GenBank登录号AF212040）。小鼠、人类和大鼠启动子序列的点阵比较表明，小鼠启动子与人类同源，与大鼠启动子同源性更强。与人类和大鼠启动子一样，小鼠启动子缺乏规范的TATA-box或TATA-like序列，但它具有一个或可能两个启动子（Inr）或Inr-like序列。能量点图分析预测小鼠启动子由3个结构域组成：(1)3'结构域包含NF-kappa B响应元件、camp响应元件（CRE）、Inr或Inr样元件、Spl结合位点和Oct - 1。(2)中间结构域包含另一个Sp1结合位点、E-box和E2F结合位点；(3)5′结构域包含tpa响应元件（TRE）和串联沉默元件。无论是促进敏感型还是抗性型JB6小鼠表皮细胞的cyclin D1启动子序列，除了一些微小的差异外，基本上与小鼠基因组克隆确定的序列相同。由于TPA不仅可以通过TRE，还可以通过启动子中的CRE和NF-kappa B应答元件刺激cyclin D1的表达，因此我们初步提出了一系列事件，这些事件可能导致TPA诱导的、不依赖于锚定的cyclin D1和a在促进敏感的JB6小鼠表皮细胞中合成。
Cyclin D1 is a cell cycle regulatory protein, which acts as a growth factor sensor to integrate extracellular signals with the cell cycle machinery, particularly during G1 phase of the cell cycle. Previous study using promotion-sensitive JB6 mouse epidermal cells, an in vitro model of the promotion stage of multistage carcinogenesis, showed that the expression of cyclin D1 is stimulated in the presence (but not in the absence) of 12-O-tetradecanoylphorbol-13-acetate (TP,A) in these cells maintained under anchorage-independent culture conditions. In the present study, to explore the molecular basis of this observation, the promoter region of mouse cyclin D1 gene was cloned and sequenced (GenBank accession number AF212040). Dot matrix comparison of mouse, human and rat promoter sequences indicated that the mouse promoter is homologous to the human and more: so to the rat promoters. The mouse promoter, like human and rat promoters, lacks canonical TATA-box or TATA-like sequence, but it has one or possibly two initiator (Inr) or Inr-like sequences. Energy dot plot analysis predicted that the mouse promoter consists of three domains: (1) the 3' domain contains NF-kappa B response element, cAMP-response element (CRE), Inr or Inr-like elements, Spl binding site and Oct 1. (2) the middle domain contains another Sp1 binding site, E-box and E2F binding site and (3) the 5' domain contains TPA-response element (TRE) and a tandem silencer element. The cyclin D1 promoter sequence of either promotion-sensitive or resistant JB6 mouse epidermal cells was, except for a few minor differences, essentially identical to the sequence determined for a mouse genomic clone. Since TPA is capable of stimulating the expression of cyclin D1 not only through TRE but also through CRE and NF-kappa B response element in the promoter, we tentatively propose a sequence of events that possibly leads to TPA-induced, anchorage-independent synthesis of cyclins D1 and A in the promotion-sensitive JB6 mouse epidermal cells.