Strefford J C, Lane T M, Hill A, LeRoux L, Foot N J, Shipley J, Oliver R T D, Lu Y-J, Young B D
Cancer Research UK Medical Oncology Unit, Queen Mary and Westfield College, Charterhouse Square, London, UK.
Cytogenet Genome Res. 2006;112(1-2):45-52. doi: 10.1159/000087512.
Although chromosome translocations are well-documented recurrent events in hematological malignancies and soft tissue sarcomas, their significance in carcinomas is less clear. We report here the molecular characterization of the reciprocal translocation t(1;15)(p22;q22) in the prostate carcinoma cell line, LNCaP. The chromosome 1 breakpoint was localized to a single BAC clone, RP11-290M5, by sequential FISH analysis of clones selected from the NCBI chromosome 1 map. This was further refined to a 580-bp region by Southern blot analysis. A 2.85-kb fragment spanning the der(1) breakpoint was amplified by long-range inverse PCR. The breakpoint on chromosome 1 was shown to lie between the CYR61 and the DDAH1 genes with the der(1) junctional sequence linking the CYR61 gene to the TSPAN3 (TM4SF8) gene on chromosome 15. Confirmatory PCR and FISH mapping of the der(15) showed loss of chromosome material proximal to the breakpoint on chromosome 15, containing the PSTPIP1 and RCN2 genes. On the available evidence we conclude that this translocation does not result in an in-frame gene fusion. Comparative expressed sequence hybridization (CESH) and comparative genomic hybridization (CGH) analysis, showed relative down-regulation of gene expression surrounding the breakpoint, but no gross change in genomic copy number. Real-time quantitative RT-PCR for genes around the breakpoint supported the CESH data. Therefore, here we may have revealed a gene down-regulation mechanism associated with a chromosome translocation, either through small deletion at the breakpoint or through another means of chromosome domain related gene regulation.
尽管染色体易位在血液系统恶性肿瘤和软组织肉瘤中是有充分记录的复发事件，但其在癌中的意义尚不清楚。我们在此报告前列腺癌细胞系LNCaP中相互易位t(1;15)(p22;q22)的分子特征。通过对从NCBI染色体1图谱中选择的克隆进行连续荧光原位杂交（FISH）分析，将染色体1的断点定位到单个细菌人工染色体（BAC）克隆RP11 - 290M5。通过Southern印迹分析进一步将其精确定位到一个580 bp的区域。通过长距离反向PCR扩增了一个跨越der(1)断点的2.85 kb片段。结果显示，染色体1上的断点位于CYR61和DDAH1基因之间，der(1)连接序列将CYR61基因与染色体15上的TSPAN3（TM4SF8）基因相连。对der(15)的验证性PCR和FISH定位显示，染色体15上断点近端的染色体物质丢失，该区域包含PSTPIP1和RCN2基因。根据现有证据，我们得出结论，这种易位不会导致读码框内基因融合。比较表达序列杂交（CESH）和比较基因组杂交（CGH）分析显示，断点周围基因表达相对下调，但基因组拷贝数无明显变化。对断点周围基因的实时定量逆转录PCR（RT-PCR）支持了CESH数据。因此，我们在此可能揭示了一种与染色体易位相关的基因下调机制，要么是通过断点处的小缺失，要么是通过染色体结构域相关基因调控的另一种方式。
