Isolation and Identification of Tumor suppressor gene in choriocarcinoma.

1）我们之前报道了人类7号染色体的纯合缺失存在于绒毛膜癌组织和细胞系中。我们认为7号染色体上的病变处存在抑癌作用。通过STS标记，我们从位于7q11.22的病灶中获得了多个BAC克隆。然后我们将这些 BAC 克隆引入绒毛膜癌细胞系中。用RS544-12D (B6)和RS741-8D (B7)转染的克隆体内致瘤性受到抑制。然后通过使用这些克隆作为探针，我们获得了几个抑制绒毛膜癌细胞系致瘤性的cDNA文库克隆。我们发现这些是假定的绒毛膜癌抑制基因之一。现在我们分析该基因的抑癌活性机制。2)我们制作了减去大量绒毛膜癌cDNA片段的绒毛特异性cDNA文库。其中一种未知基因，名为克隆S31，仅在绒毛中表达，但在绒毛膜癌中不表达。克隆S31大小为1.1kb，编码73个氨基酸，当该克隆导入绒毛膜癌细胞系时具有肿瘤抑制潜力。该S31与牙龈表达的cDNA克隆同源，并且位于幼年牙龈的推定病变附近。

1) We previously reported that the homozygous deletion in human chromosome7 were presented in choriocarcinoma tissues and cell lines. We thought the presence of tumor suppressor effect at that lesion in chromosome7. We have got the several BAC clones from the lesion located at 7q11.22 by using STS marker. Then we introduce these BAC clones into choriocarcinoma cell lines. The clones transfected with RS544-12D (B6) and RS741-8D (B7)were suppressed in vivo tumorigenicity. Then by using these clones for probe we got several cDNA library clones that suppressed the tumorigenicity of choriocarcinoma cell lines. We through that these were one of the putative choriocarcinoma suppressor genes. Now we analyze the mechanisms of tumor suppress activity of the genes.2) We made the villi-specific cDNA library that subtracted by large amount of choriocarcinoma cDNA fragment. One of the unknown gene, named clone S31 expressed only in villi, but not in choriocarcinoma. The size of clone S31 is 1.1 kb, coded 73 amino acids and have tumor suppressive potential when this clone were introduced into choriocarcinoma cell line. This S31 are homologous to gingiva expressed cDNA clone and located near the putative lesion of juvenile gingivatitts.