Isolation and Identification of Tumor suppressor gene in choriocarcinoma.

1)我们曾报道在绒毛膜癌组织和细胞系中发现了人类7号染色体的纯合缺失。我们认为在7号染色体的那个病变处存在肿瘤抑制作用。利用STS标记从位于7q11.22的病斑中获得了几个BAC克隆。然后我们将这些BAC克隆导入绒毛膜癌细胞系。转染RS544-12D(B6)和RS741-8D(B7)的克隆体内致瘤性受到抑制。然后以这些克隆为探针，获得了几个抑制绒毛膜癌细胞致瘤性的文库克隆。我们认为这些基因可能是绒毛膜癌抑制基因之一。2)通过大量绒毛膜癌基因片段的消减，构建绒毛组织特异的cDNA文库。其中一个未知基因命名为克隆S31，只在绒毛中表达，而在绒毛膜癌中不表达。克隆S31的大小为1.1kb，编码73个氨基酸，将其导入绒毛膜癌细胞后具有抑瘤作用。这些S31与牙龈表达的cDNA克隆同源，位于幼年性牙周炎病变附近。

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.