A zinc-finger protein, PLAGL2, induces the expression of a proapoptotic protein Nip3, leading to cellular apoptosis
A zinc-finger protein, PLAGL2, induces the expression of a proapoptotic protein Nip3, leading to cellular apoptosis
复制标题
DOI：
10.1074/jbc.m111431200
复制
发表时间：
2002-05-03
影响因子：
4.8
通讯作者：
Taketani, S
中科院分区：
文献类型：
--
作者：
Mizutani, A;Furukawa, T;Taketani, S
多形性腺瘤基因样2（PLAGL 2）蛋白含有7个C、H、锌指基序，具有DNA结合和转录激活活性，并在缺氧或缺铁时表达。为了鉴定PLAGL 2的靶基因，我们将小鼠PLAGL 2 cDNA转染Balb/c3 T3成纤维细胞和神经母细胞瘤Neuro 2a细胞。通过TUNEL（末端脱氧核苷酸转移酶介导的dUTP缺口末端标记）、DNA片段化、碘化丙啶染色和膜联蛋白V与细胞表面的结合测定，通过PLAGL 2的表达诱导两种细胞发生凋亡。用铁螯合剂去铁胺处理细胞，导致细胞凋亡诱导，同时PLAGL 2在细胞核中积累。PLAGL 2在Balb/c3 T3细胞中的表达导致促凋亡因子Nip 3的mRNA表达，Nip 3可以与Bcl-2二聚化。去铁胺处理的细胞中Nip 3 mRNA也被诱导。此外，含有低氧应答元件的Nip 3启动子被PLAGL 2激活，不依赖于低氧诱导因子-1（HIF-1）。将小鼠Nip 3 mRNA的反义寡核苷酸转染到PLAGL 2表达细胞中，与正义寡核苷酸转染的细胞相比，凋亡细胞减少。尽管在缺氧条件下DNA-HIF-1结合活性被激活，但在表达P1 PLAGL 2后既没有观察到HIF-1 α的积累也没有观察到HIF-1的激活。这些结果表明PLAGL 2位于HIF-1的下游，并表明PLAGL 2作为与HIF-1相关的肿瘤抑制因子发挥作用。
Pleomorphic adenomas gene-like 2 (PLAGL2) protein containing seven C,H, zinc finger motifs exhibits DNA binding and transcriptional activation activity and is expressed in response to hypoxia or iron deficiency. To identify the target genes of PLAGL2, we transfected mouse PLAGL2 cDNA into Balb/c3T3 fibroblasts and neuroblastoma Neuro2a cells. Both cells were induced to undergo apoptosis by the expression of PLAGL2 as judged by assays of TUNEL (terminal deoxynucleotidyltransferase-mediated dUTP nick end-labeling), DNA fragmentation, propidium iodide staining, and the binding of annexin V to the cell surface. The treatment of the cells with an iron chelator, desferrioxamine, resulted in the induction of apoptosis with a concomitant accumulation of PLAGL2 in the nucleus. The expression of PLAGL2 in Balb/c3T3 cells led to the mRNA expression of a proapoptotic factor, Nip3, which can dimerize with Bcl-2. Nip3 mRNA was also induced in desferrioxamine-treated cells. Furthermore, the Nip3 promoter containing a hypoxia-responsive element was activated by PLAGL2, independent of hypoxia-inducible factor-1 (HIF-1). The transfection of antisense oligonucleotide to mouse Nip3 mRNA into PLAGL2-expressing cells led to a decrease in apoptotic cells compared with sense oligonucleotide-transfected cells. Despite the activation of DNA-HIF-1 binding activity under hypoxic conditions, neither an accumulation of HIF-1alpha nor the activation of HIF-1 was observed following the expression of P]PLAGL2. These results indicate that PLAGL2 is located downstream of HIF-1 and suggest that PLAGL2 functions as a tumor suppressor in association with HIF-1.