应用EST策略鉴定人类新基因UBAP1的数字化差异表达图谱

Identification of Digital Differential Expression Patterns of a Novel Human Gene(UBAP1) by an Expressed Sequence Tag Strategy

背景与目的:UBAP1(ubiquitinassociatedprotein1)基因是我们先前在人类染色体9p21-22鼻咽癌杂合性丢失(lossofheterozygosity,LOH)高频区所获得的一个鼻咽癌相关新基因。进一步地,我们应用EST策略鉴定UBAP1基因在多种肿瘤组织中的差异表达谱。方法:采用基于生物信息学的电子杂交方法,即以UBAP1基因的全长cDNA为“探针”,利用计算机对人类表达序列标签(expressedsequencetag,EST)和Unigene等数据库中代表UBAP1的EST在各类肿瘤及相应正常组织cDNA文库中的分布进行综合分析,研究UBAP1基因的数字化差异表达图谱。同时采用差异RT-PCR方法对UBAP1在3种肿瘤活检组织中的差异表达进行验证。结果:电子杂交结果表明UBAP1基因不仅在42种人类正常组织中广泛表达,而且在11种肿瘤组织中存在可能的表达差异,尤其是在脑瘤、乳腺癌、结肠癌、皮肤癌、睾丸癌和宫颈癌等肿瘤组织中表达显著下调(P<0.05),而在肾癌、胰腺癌中高表达(P<0.05)。进一步采用差异RT-PCR方法发现UBAP1基因在64%的脑膜瘤和72%的结直肠癌活检组织中具有明显表达缺失/下调。结论:UBAP1基因有可能与多种肿瘤的发生发展密切相关,有必要深入研究UBAP1基因的表达异常参与肿瘤发生发展的分子机制。

Background &Objectives:This study was designed to identify d ifferential expression patterns in tumor and normal tissues of the human novel gene,UBAP1,a putative nasopharyngeal carcinoma (NPC)relate gene,which is located at human chromosome 9p21-22where loss of heterozygosity frequently occurs in NPC.Methods:Based on the generation of expressed sequence ta gs(ESTs ),in the authors'electronic Northern blot,complete cDNA of ubap1gene wa s taken as a 'probe'sequence,and human EST Database search of GenBank was carried out using B LASTn programs.A report generated in a BLAST search of ubap1gene sequence against an EST database consisting o f such'pedigree'ESTs allows the inference of the gene's tissue di stribution.Furthermore,differential RT-PCR was used to desc ribe the expression patterns of ubap1in partial tumor tissues.Results:Database surveys indicated ubap1gene was not only ubi quitously expressed in many normal tissues with various levels b ut also differentially expressed in different tumor tissues,especia lly down-regulated in multiple neoplastic tissues such as brain,br east,skin,colon,testis,and uterus tumor tissues.Furthermore,differential RT-PCR analysis demonstrated expression of ubap1wa s down-regulated or absent in 7of 11(64%)meningioma samples and 13of 18(72%)colorectal tumor tissues respectiv ely.Conclusions:The authors present an EST approach t hat proved to be useful for the identification of differential exp ression patterns of ubap1in differe nt tumors.These findings could be valuable for the investigation of the mechanism of UBAP1gene exhibiting differential expression,potentially involved in t he progression of multiple cancers.