title: Jasmonate-responsive expression of paclitaxel biosynthesis genes in Taxus cuspidata cultured cells is negatively regulated by the bHLH transcription factors TcJAMYC1, TcJAMYC2, and TcJAMYC4.
abstract: Taxus cell suspension culture is a sustainable technology for the industrial production of paclitaxel (Taxol®), a highly modified diterpene anti-cancer agent. The methyl jasmonate (MJ)-mediated paclitaxel biosynthetic pathway is not fully characterized, making metabolic engineering efforts difficult. Here, promoters of seven genes (TASY, T5αH, DBAT, DBBT, PAM, BAPT, and DBTNBT), encoding enzymes of the paclitaxel biosynthetic pathway were isolated and used to drive MJ-inducible expression of a GUS reporter construct in transiently transformed Taxus cells, showing that elicitation of paclitaxel production by MJ is regulated at least in part at the level of transcription. The paclitaxel biosynthetic pathway promoters contained a large number of E-box sites (CANNTG), similar to the binding sites for the key MJ-inducible transcription factor AtMYC2 from Arabidopsis thaliana. Three MJ-inducible MYC transcription factors similar to AtMYC2 (TcJAMYC1, TcJAMYC2, and TcJAMYC4) were identified in Taxus. Transcriptional regulation of paclitaxel biosynthetic pathway promoters by transient over expression of TcJAMYC transcription factors indicated a negative rather than positive regulatory role of TcJAMYCs on paclitaxel biosynthetic gene expression.
authors.affiliation: Department of Biology, University of Massachusetts Amherst, MA, USA.
authors.forename: Sangram K
authors.initials: SK
authors.lastname: Lenka
authors.affiliation: Department of Biology, University of Massachusetts Amherst, MA, USA ; Plant Biology Graduate Program, University of Massachusetts Amherst, MA, USA.
authors.forename: N Ezekiel
authors.initials: NE
authors.lastname: Nims
authors.affiliation: Plant Biology Graduate Program, University of Massachusetts Amherst, MA, USA ; Department of Chemical Engineering, University of Massachusetts Amherst, MA, USA.
authors.forename: Kham
authors.initials: K
authors.lastname: Vongpaseuth
authors.affiliation: Department of Biology, University of Massachusetts Amherst, MA, USA.
authors.forename: Rosemary A
authors.initials: RA
authors.lastname: Boshar
authors.affiliation: Plant Biology Graduate Program, University of Massachusetts Amherst, MA, USA ; Department of Chemical Engineering, University of Massachusetts Amherst, MA, USA.
authors.forename: Susan C
authors.initials: SC
authors.lastname: Roberts
authors.affiliation: Department of Biology, University of Massachusetts Amherst, MA, USA ; Plant Biology Graduate Program, University of Massachusetts Amherst, MA, USA.
authors.forename: Elsbeth L
authors.initials: EL
authors.lastname: Walker
keywords: E-box; JA-MYC; MYC2; Taxus cuspidata; methyl jasmonate; paclitaxel