As one member of the Ras super family, Rheb is an upstream regulator of mTOR signaling pathway, which regulates the process of cell-growth, proliferation and differentiation. In order to study the relationship between Rheb and mTOR in Inner Mongolian Cashmere goat （Capra hircus） cells, Ras homolog enriched in brain （Rheb） gene eDNA was amplified by RT-PCR. It is 555 bp in length and includes the complete ORF encoding 184 amino acids （GenBank accession no. HM569224）. The full eDNA nucleotide sequence has a 99% identity with that of sheep, 98% with cattle and 93% with human while their amino acids sequence shares identity with 98, 97 and 97% of them, correspondingly. The bioinformatics analysis showed that Rheb has a Ras family domain, two casein kinase II phosphorylation sites, two ATP/GTP-binding sites motifA （P-loop）, a prenyl group binding site （CAAX box）. Tissue-specific expression analysis performed by semi- quantitative RT-PCR. The Rheb gene was expressed in all the tested tissues and the highest level ofmRNA accumulation was detected in brain, suggesting that Rheb played an important role in goat cells.
ZHENG Xu YANG Jiao-fu WANG Xiao-jing LIANG Yan WU Man-lin SHI Jie-jun ZHANG Tao QIN Yin LI Shu-yu HAO Xi-yan WANG Zhi-gang LIU Dong-jun
To detect the mammalian target of rapamycin （mTOR） expressed in Cashmere goat fetal fibroblasts （GFb）, mTOR gene was cloned from Inner Mongolia Cashmere goat （Capra hircus） and expressed in Escherichia coli followed by immunizing mice with the purified recombinant protein as an irnmunogen to produce the anti-goat mTOR recombinant polyclonal antibody. Antiserum was collected from the immunized mice after the fifth immunization and its titer was determined with enzyme-linked immunosorbent assay （ELISA）. The results showed that the recombinant polyclonal antibody had a titer 1：200000 and could react with the roTOR expressed in GFb cells with a specific and sensitive affinity. Western blot showed that mTOR expression and phospho-mTOR （Ser 2448） activity were inhibited when GFb cells were treated with CCI-779, an mTOR specific inhibitor.
