人乙酰转移酶样蛋白的核仁定位及在肿瘤中的表达  

Nucleolar localization of human acetyltransferase-like protein and its expression in tumors

作　　者：关立照[1] 沈棋[1] 孙颖[1] 王教辰[1] 龚一蕾[1] 侯琳[1] 张波[1] 

机构地区：[1]北京大学基础医学院病理学系,北京100083

出　　处：《北京大学学报（医学版）》2008年第4期347-351,共5页Journal of Peking University:Health Sciences

基　　金：国家自然科学基金(30770830)资助~~

摘　　要：目的:探讨端粒酶调节相关蛋白——人乙酰转移酶样蛋白(hALP)核仁定位的分子基础及相关功能。方法:利用免疫荧光及免疫电镜的方法检测hALP在HeLa及Saos2细胞中的分布情况,通过rDNA荧光原位杂交及免疫荧光观察hALP与rDNA定位关系,利用RNA干扰的方法进一步证明其核仁定位性,通过基因重组构建包含不同长度片段的hALP基因的真核表达质粒并转染细胞以探讨其核仁定位的分子基础,运用免疫组织化学的方法检测hALP在多种肿瘤组织中的表达情况。结果:hALP在HeLa及Saos2细胞分裂间期主要定位于核仁,并与rDNA有共定位。免疫电镜显示,hALP主要位于核仁的颗粒区;RNA干扰后hALP在核仁区的染色明显减弱;其核仁定位由hALP羧基端的功能域介导。hALP蛋白表达于多种人肿瘤细胞(如平滑肌肉瘤、原始神经外胚叶瘤、神经母细胞瘤、黑色素瘤、前列腺癌及肾透明细胞癌)的核仁。结论:hALP蛋白具有明显的核仁定位性,并由其特异性的功能域介导,hALP可表达于多种肿瘤细胞的核仁,其意义值得进一步探讨。Objective：To confirm the nucleolar localization of telomerase-regulation associated proteinhuman N-acetyltransferase-like protein （hALP） and its associated functions. Methods： Immunofluoresent staining and immunoelectron microscopy were used to detect the distribution of hALP in HeLa and Saos2 cells, and the co-localization of hALP and rDNA was analyzed by fluorescence in situ hybridization and immunofluoresence, RNAi was performed to further verify the nucleolar localization of hALP, A series of eukaryotic expression plasmids carrying various portions of hALP sequence were constructed and transiently transfected to HeLa and Saos2 cells, The expression of hALP in tumor tissues was stained by immunohistochemistry. Results： hALP distributed predominantly in the nucleoli of HeLa and Saos2 cells, and colocalized with rDNA. Granular component was the precise distribution of hALP in the nucleolus under electron microscope. Nucleolar signals for hALP reduced significantly in cells transfected with hALP siRNA. The carboxy terminus of hALP including residues 549 - 834 was necessary for its nucleolar localization, hALP could be detected in the nucleoli of many kinds of tumor cells, including leiomyosarcoma, primitive neuroectodermal tumor, neuroblastoma, melanoma, prostatic cancer, and clear cell renal carcinoma. Conclusion： hALP is a nucleolar protein, and the nucleolar localization is mediated by its carboxy terminal domain, and hALP could be detected in the nucleoli of many tumor tissues, which is worthy of further investigation.

关 键 词：人乙酰转移酶样蛋白 细胞核仁 肿瘤 

分 类 号：R730.2[医药卫生—肿瘤]