中文摘要：

Rab GTPase家族成员基因及其调节囊泡膜运输途径功能已有许多报道，但Rab26蛋白分子的结构和功能仍不清晰．通过生物信息学分析，并在人脑cDNA文库中克隆了一个新的Rab26基因全长cDNA序列，长1656bp，与已发表的基因序列相比，在48-50位插入了GCC，在956位T被C取代，而在1197位G被A取代．该序列包含一个771bp完整的开放阅读框（ORF），编码256个氨基酸残基的Rab26蛋白，分子质量为27．9ku（GenBank登录号No．AY646153），而非如以往报告的190个氨基酸残基．GFP荧光标记全长Rb26在哺乳动物细胞中表达显示，Rab26主要呈现在细胞膜状结构相联系的分布，发现该基因高表达能显著增强PE标记的红色异源蛋白质的吞噬．还应用逆转录．聚合酶链反应对多种人肿瘤细胞Rb26表达进行了研究，结果显示，Rab26在Acc2、SPC-A1，K562以及HeLa等肿瘤细胞株呈高表达，而在SMMOL／LC-7721、HepG2、Caco2等肝和肠上皮细胞株中则不表达，值得进一步深入研究．

英文摘要：

Rab GTPases serve as master regulators of vesicular membrane transport on both the exo- and endocytic pathways. Though there are many reports on Rab proteins, the function of these small proteins still remain in speculation. And no report has ever clarified the character of human Rab26. Here it was reported that a novel Rab protein Rab26 is membranous organelle related and involved in endocytosis of HeLa cells. By using RT-PCR method a novel Rab26 eDNA full-length eDNA of Rab26 that is 1656 bp was identified. The cDNA sequence that at 1197 is ＇A＇ other than ＇G＇, while ＇C＇ at 956 substitutes for ＇T＇, and has ＇GCC＇ insertion at 48 to 50 compared with published sequences. The complete open reading flame （ORF） is 771 bp in length encoding 256-residue protein with a calculated molecular mass of 27.9 ku （GenBank accession No.AY646153）, rather than a shorter one with 190-amino acid residue as reported previously. GFP labeled full-length Rab26 expression showed that Rab26 was mainly sublocated in membranous organelles and could enhance endocytosis which means could took PIE labeled protein as an endocytic tracer. RT-PCR analysis showed Rab26 was detected to express in several kinds of adenocarcinoma cell lines such as Ace2, AccM, SPC-A1 and HeLa cell lines, which indicated that Rab26 expression might be associated with some carcinomas.