DNA Fragmentation Factor 45 (DFF45) gene at 1p36.2 is homozygously deleted and encodes variant transcripts in neuroblastoma cell line
DNA Fragmentation Factor 45 (DFF45) gene at 1p36.2 is homozygously deleted and encodes variant transcripts in neuroblastoma cell line
复制标题
DOI：
10.1038/sj.neo.7900141
复制
发表时间：
2001-03-01
期刊：
影响因子：
4.8
通讯作者：
Hayashi, Y
中科院分区：
文献类型：
--
作者：
Yang, HW;Chen, YZ;Hayashi, Y
最近的杂合性丢失（洛）研究表明，在神经母细胞瘤（NB）中，1号染色体短臂（Ip）上存在两个以上的抑癌基因。为了鉴定NE中的候选抑癌基因，我们使用高密度STS图谱在20个NE细胞系中寻找纯合缺失，该图谱跨越染色体1 p36，NE中常见的洛区域。我们发现，DNA片段化因子45亚基（DFF 45）基因在NE细胞系NB-1中同源缺失，DFF 45是DFF 90的伴侣，这两种分子都是caspase 3诱导细胞凋亡所必需的，DFF 35是DFF 45的剪接变体，是DFF 40的抑制剂。采用逆转录-聚合酶链反应（RT-PCR）和RT-PCR-单链构象多态性（RT-PCR-single strand conformation polymorphism）方法检测20株NE细胞系DFF 45基因的表达和突变。在NE细胞系中发现了DFF 45基因的一些新的变体转录本，而在正常肾上腺和外周血中未发现。这些变异体可能不作为DFF 40的伴侣，但作为抑制剂，如DFF 35，从而破坏DFF 45和DFF 40之间的平衡。在任何NE细胞系中未发现DFF 45基因的突变，表明DFF 45不是NE的肿瘤抑制基因。但是呢？NB-I细胞系中DFF 45基因的纯合缺失可能意味着在该区域中存在未知的肿瘤抑制基因。
Recently, loss of heterozygosity (LOH) studies suggest that more than two tumor suppressor genes lie on the short arm of chromosome 1 (Ip) in neuroblastoma (NB). To identify candidate tumor suppressor genes in NE, we searched for homozygous deletions in 20 NE cell lines using a high-density STS map spanning chromosome 1p36, a common LOH region in NE. We found that the 45-kDa subunit of the DNA fragmentation factor (DFF45) gene was homozygously deleted in an NE cell line, NB-I, DFF45 is the chaperon of DFF90, and both molecules are necessary for caspase 3 to induce apoptosis, DFF35, a splicing variant of DFF45, is an inhibitor of DFF40. We examined 20 NE cell lines for expression and mutation of DFF45 gene by reverse transcription (RT)-polymerase chain reaction (PCR) and RT-PCR-single-strand conformation polymorphism. Some novel variant transcripts of the DFF45 gene were found in NE cell lines, but not in normal adrenal gland and peripheral blood. These variants may not serve as chaperons of DFF40, but as inhibitors like DFF35, thus disrupting the balance between DFF45 and DFF40, No mutations of the DFF45 gene were found in any NE cell line, suggesting that the DFF45 is not a tumor suppressor gene for NE. However? homozygous deletion of the DFF45 gene in the NB-I cell line may imply the presence of unknown tumor suppressor genes in this region.