中文摘要：

去泛素化酶25（Ubiquitin-specific protease25,USP25）作为蛋白泛素化降解过程的负性调节因子,广泛参与病毒免疫、肿瘤发生、转移、蛋白修饰折叠等一系列的病理和生理过程,在小鼠胚胎中,该基因主要表达于增殖的神经上皮细胞和有丝分裂后的神经元,但是其在整个胚胎发育早期时空的细致表达尚未详尽刻画.作者克隆了模式动物非洲爪蛙（Xenopus laevis）去泛素化酶25,通过胚胎原位杂交和半定量RT-PCR方法研究了其在早期胚胎中的时空表达情况.USP25蛋白序列在进化上,从斑马鱼、鸡胚、爪蛙、小鼠到人具有高度的保守性,提示该蛋白在各物种间具有相似的功能.数据表明,USP25在非洲爪蛙中母源性表达于动物极区域,在整个早期胚胎发育过程中其mRNA表达量比较恒定,神经板时期（第14期）USP25主要在胚胎神经板外侧、前部基板和表皮表达;发育后期该基因主要表达于中枢神经系统、心脏、胰腺以及胃和十二指肠原基,提示该基因在这些器官和组织发育中发挥作用.

英文摘要：

Ubiquitin - specific protease 25, a negative regulator of ubiquitin - proteasome complex, involves in se- ties of physical and pathological functions including viral invading, tumor genesis, metastasis, protein - folding etc. In mouse embryos, USP25 was found in proliferative neuroepithelial cells and postmitotic neurons. However, its temporal spatial expression pattern and putative roles in early embryo were poorly described. We cloned USP25, and researched its developmental expression pattern in Xenopus laevis embryos by in situ hybridization and RT - PCR. USP25 proteins are evolutionary conserved from D. redo, G. gallus, X. laevis, M. musculus to H. sapiens, im- plying important and similar function among different vertebrate animals. Our data reveal USP25 is maternally ex- pressed in the animal hemisphere. Its expression level is constant among the whole developmental stage in Xeno- pus. At neural plate stage, USP25 appears mainly in the outer region of neural plate, anterior placode, and epider- mis. At tailbud and tadpole stage, the transcript of USP25 is detected in the central nerve system, cardiovascular anlage , pancreas, stomach and duodenum area, suggesting its putative roles in the organs development.