基于ChIP-Seq进行肿瘤睾丸抗原XAGE-1b基因表达蛋白的DNA结合位点鉴定

XAGE-1b（X antigen family member 1B）属于XAGE亚家族，是一种肿瘤 睾丸抗原（cancer/testis antigen，CTA），表达于正常人睾丸组织和多种类型的肿瘤细胞中.本实验室前期研究发现,该基因在涎腺腺样囊性癌高转移细胞系中呈高表达.为了进一步研究XAGE-1b下游调控基因，本实验采用ChIP Seq技术筛查XAGE 1b蛋白质可能存在的DNA结合片段. 结果发现,XAGE-1b下游调控基因富集于细胞分裂（cell division，P-Value＝7.95e-04）、细胞周期调控（cell cycle，P-Value＝5.532e-03）、及癌症相关基因（GESA/MSigDB module_11，P-Value＝2.010e-06）中．同时发现,XAGE-1b下游调控多个基因的表达产物（NCBI/interactions 22827，P-Value＝4.678e-06）能与原癌基因c-Myc的启动子抑制蛋白PUF60发生蛋白质相互作用，并通过qPCR进行了验证．这些研究对阐明XAGE-1b在肿瘤细胞的增殖和转移中的作用有重要意义.

Identification of Cancer/Testis Antigen XAGE-1b DNA Binding Sites by ChIP-Seq Method

XAGE-1b is a cancer/testis antigen and belongs to XAGE subfamily. XAGE-1b protein was found in testis and varieties of tumor tissues. Our previous study found the expression of XAGE-1b in the high metastatic cell line of adenoid cystic carcinoma of salivary gland is significantly higher than in low metastatic cell line. In this study, we profiled the genome wide DNA binding sites of XAGE 1b by chromatin immunoprecipitation followed by high throughput sequencing (ChIP-Seq) on Illumina HiSeq 2000 platform. The downstream genes were indentified and was found highly enriched in cell division（P-Value＝7.95e-04）, cell cycle（P-Value＝5.532e-03）in GOSlim analysis and in cancer modules (GESA/MSigDB　module_11, P-Value＝2.010e-06) in HOMER analysis. The result also relvealed that XAGE 1b protein regulates c-Myc indirectly by promoter repressor protein PUF60 binding proteins such as PABPC1. It proposed that XAGE-1b may play an important role in metastatic, proliferation and tumorigenesis through c-Myc-dependent pathway.