title: Expression of recombinant alpha and beta tubulins from the yew Taxus cuspidata and analysis of the microtubule assembly in the presence of taxol.
abstract: Taxol was originally isolated from the yew Taxus brevifolia. Because taxol inhibits the depolymerization of microtubules, the presence of a self-resistance mechanism in Taxus spp. was hypothesized. The cloning of the cDNA for alpha and beta tubulins from Taxus cuspidata and those from the human embryonic kidney cell line HEK293T revealed that the (26)Asp, (359)Arg, and (361)Leu residues in the human beta tubulin, which are important for taxol binding, were replaced with Glu, Trp, and Met in the beta tubulin of T. cuspidata, respectively. The microtubule assembly of the recombinant alpha and beta tubulins was monitored turbidimetrically, and the results clearly demonstrated that the microtubule from T. cuspidata is less sensitive to taxol than that from HEK293T cells. The Taxus microtubule composed of the wild-type alpha tubulin and the beta tubulin with the E26D mutation restored the sensitivity to taxol. We thus postulated that the mutation identified in the beta tubulin of T. cuspidata plays a role in the self-resistance of this species against taxol.
authors: a Graduate School of Agricultural Science , Tohoku University , Sendai , Japan.
authors: Yuma
authors: Y
authors: Kudo
authors: Akihiro
authors: A
authors: Abe
authors: Kumiko
authors: K
authors: Ito
authors: Yuko
authors: Y
authors: Cho
authors: Mari
authors: M
authors: Yotsu-Yamashita
authors: Keiichi
authors: K
authors: Konoki
mesh_terms: D019943:Amino Acid Substitution; D003001:Cloning, Molecular; D016384:Consensus Sequence; D018506:Gene Expression Regulation, Plant; D057809:HEK293 Cells; D006801:Humans; D008870:Microtubules / Q000187:drug effects* / Q000378:metabolism*; D015394:Molecular Structure; D017239:Paclitaxel / Q000494:pharmacology*; D011485:Protein Binding / Q000187:drug effects; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D016415:Sequence Alignment; D020946:Taxus / Q000737:chemistry* / Q000187:drug effects / Q000235:genetics* / Q000378:metabolism; D014404:Tubulin / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D050257:Tubulin Modulators / Q000494:pharmacology
chemical_list: D011994:Recombinant Proteins; D014404:Tubulin; D050257:Tubulin Modulators; D017239:Paclitaxel
keywords: microtubule; self-resistance; taxol; tubulin