摘要
目的克隆食管癌缺失的基因。方法采用简化的基因组消减杂交方法，从食管癌细胞系ＥＣ８７１２和ＥＣ８７３３中分离缺失的ＤＮＡ片段。继用Ｓｏｕｔｈｅｒｎｂｌｏｔ和ＰＣＲ技术检测这些片段在２０对食管癌及其癌旁组织标本中的缺失。结果获得７条食管癌细胞系缺失的基因片段，分别命名为１２Ｈ１、１２Ｈ２、３３Ｈ３、３３Ｈ４、１２Ｂ１、３３Ｂ２和３３Ｂ３。克隆测序后确定１２Ｈ１为５１２ｂｐ，１２Ｈ２为４２８ｂｐ，３３Ｈ３为５０９ｂｐ，３３Ｈ４为３５５ｂｐ，１２Ｂ１约为６８０ｂｐ（部分测序），３３Ｂ２为５１９ｂｐ，３３Ｂ３为４２５ｂｐ。同源性比较发现１２Ｈ１与３３Ｈ３互补同源，且与人基因组中定位于４Ｐ一新的核苷酸序列９８％同源。３３Ｈ４与定位于人１７号染色体上的α卫星序列８７％同源。１２Ｂ１与人Ｌ１家族中具有转座功能且带有开放阅读框的成员９０％同源。１２Ｈ２、３３Ｂ２和３３Ｂ３在基因库中尚无同源序列。这些片段在食管癌组织中的缺失频率为２０％～６０％，癌旁组织中为１０％～２０％。结论３３Ｈ４可能伴随食管癌中关键基因的缺失而缺失，１２Ｂ１通过转座作用抑制肿瘤的发生，而１２Ｈ１／３３Ｈ３、１２Ｈ２、３３Ｂ２和３３Ｂ３为食管癌的候选抑癌基?
Objective To clone tumor suppressor genes associated with human esophageal cancer (EC). Methods DNA fragments deleted from cell lines of esophageal cancer EC8712 and EC8733 were isolated by using modified genomic substractive hybridization. Twenty EC tissues paired with adjacent normal mucosa were analysed by Southern blot and PCR with these fragments as probes. Results Seven DNA fragments deleted from EC cell lines obtained were named as 12H1, 12H2, 33H3, 33H4, 12B1, 33B2 and 33B3. Sequencing revealed their size of 512bp, 428bp, 509bp, 355bp, 680bp (partially sequencing), 519bp and 425bp, respectively. 12H1 and 33H3 showed high homology (98%) to a new repeated sequence in human genome. 33H4 displayed 87% nucleotide identity with human alphoid like repetitive sequence located on chromosome 17.12B1 was homologous (90%) to LINE 1 transoposon containing two open reading frames. 12H2, 33B2 and 33B3 were novel sequences. These DNA fragments were deleted in 20%～60% of EC tissues and in 10%～20% of adjacent mucosa. Conclusions Loss of 33H4 may be accompanied by deletion of an adjacent gene. 12B1 as transposon may suppress the tumorigenesis by activating suppressor genes or/and by inactivating oncogenes. 12H1/33H3 12H2, 33B2 and 33B3 may be candidates of tumor suppressor genes associated with the development and the progression of esophageal cancer.
出处
《中华医学杂志》
CAS
CSCD
北大核心
1997年第10期737-741,共5页
National Medical Journal of China
