人Elongator复合物Elp3亚基基因可显著补偿酵母elp3缺失菌株的生长缺陷

从HeLa细胞中分离的人的Elongator复合物在组成及与RNAPⅡ的作用方式上与酵母的Elongator复合物十分相似．但对其功能研究极少。为了研究人的Elongator复合物催化亚基Elp3的功能，将人elp3等基因转入酵母elp3基因缺失的突变菌株（elp3△菌株），并对转化菌株进行功能互补实验和ssa和pho5基因表达分析，结果表明人elp3基因可显著恢复突变菌株对高温和Caffeine的敏感性．在低磷条件下显著补偿了突变株ph05基因表达延迟的缺陷．并可在热激条件下提高ssa3基因的表达。含酵母elp3非HAT区和人elp3 HAT区的融合yhelp3对上述缺陷有着更强的补偿能力。而HAT区催化结构域缺失的yhelp3HAT-没有任何补偿能力．表明人Elp3亚基可能与酵母的该亚基功能相似．人Elp3的HAT活性也为其行使功能所必需。

The elp3 subunit of human elongator complex ignificantly complemented the growth defects of yeast elp3delta strain]

The human elongator complex was found to be very similar to the yeast Elongator both in composition and its interaction with RNA polymerase II. But little is known about its functions in vivo. In this study, we analyzed the functions of the help3, the catalytic subunit of human Elongator, using a yeast complementation system. The results indicated that help3 was able to significantly complement the growth defects of the elp3delta yeast strain under high temperature and caffeine conditions. Gene expression analysis showed that help3 significantly resumed the slow activation of the pho5 gene under the low phosphate condition, and when heat shocked it increased the expression level of ssa3 gene. The yhelp3 containing the HAT domain of human elp3 and the remainder of yeast elp3 had a higher complementation ability than human elp3, while the yhelp3HA T- with the catalytic HAT domain deleted had no complementation ability. These results implicate that human Elp3 subunit had similar functions to those of the yeast, and the HAT activity of human Elp3 was essential for its function.