TMSG-1是1999年北京大学医学部首先克隆出的肿瘤转移抑制基因。我们前期研究首次发现TMSG-1含Homeodomain结构域的截短体可以入核，进一步发现TMSG-1蛋白具有核定位信号及DNA结合功能域，因此我们在国内外首次提出TMSG-1蛋白可能入核并有转录因子活性。本课题重点研究肿瘤细胞TMSG-1入核及机制和转录调节作用。包括：①探测肿瘤细胞内TMSG-1蛋白自然状态或特定刺激下能否入核，TMSG-1与His融合进行免疫荧光及Westernblot检测其全长及截短体哪段可入核；②据生物信息学预测进行定点突变，确定TMSG-1核定位信号；③探讨TMSG-1入核机制，据生物信息学预测，免疫共沉淀探测与其相互作用的核输入蛋白；④荧光素酶报告基因检测TMSG-1是否具有转录调节功能；⑤染色质免疫共沉淀与基因芯片对其下游靶基因进行筛选，并通过荧光素酶、上调表达和RNA干扰验证转录调节作用。

TMSG-1 was first identified as a new tumor metastasis suppressor gene by the Pathology Department of Health Science Center Pecking University in 1999. Our previous study for the first time found the truncated variants of TMSG-1 including Homeodomain could enter the nucleus.Then we analysed the protein sequence of TMSG-1 and we found it had nuclear localization signal (NLS) and DNA binding domain. Therefore, we for the first time proposed TMSG-1 could play the role of transcriptional factor after entering the nucleus. Our study aimes to investigate whether TMSG-1 could enter nucleus, as well as to detect its transcription regulatory function. The study comprises of the following aspects: ① Observing whether the inherent TMSG-1 in tumor cells could enter the nucleus under natural satus or certain stimulus. Detecting the truncated variants of TMSG-1 which could enter the nucleus using immunofluorescence and luser confocal microscopy after fused with His tag; ②According to the prediction of bioinformatics, carrying out site-specific mutation to identify the NLS of TMSG-1; ③Revealing the importin interacted with TMSG-1 by bioinformatics and immunoprecipitation to give insight into the mechanisms through which TMSG-1 enters the nucleus; ④Detecting the transcription regulatory function of TMSG-1 through luciferase report gene; ⑤Combining the chromatin immunoprecipitation and gene chip to screen and classify the down stream genes of TMSG-1 protein, as well as confirming the transcription regulatory function of TMSG-1 playing on the target genes through luciferase report gene, overexpression and RNA interfernce of TMSG-1.