title: Production of biologically active human thioredoxin 1 protein in lettuce chloroplasts.
abstract: The production of human therapeutic proteins in plants provides opportunities for low-cost production, and minimizes the risk of contamination from potential human pathogens. Chloroplast genetic engineering is a particularly promising strategy, because plant chloroplasts can produce large amounts of foreign target proteins. Oxidative stress is a key factor in various human diseases. Human thioredoxin 1 (hTrx1) is a stress-induced protein that functions as an antioxidant against oxidative stress, and overexpression of hTrx1 has been shown to suppress various diseases in mice. Therefore, hTrx1 is a prospective candidate as a new human therapeutic protein. We created transplastomic lettuce expressing hTrx1 under the control of the psbA promoter. Transplastomic plants grew normally and were fertile. The hTrx1 protein accumulated to approximately 1% of total soluble protein in mature leaves. The hTrx1 protein purified from lettuce leaves was functionally active, and reduced insulin disulfides. The purified protein protected mouse insulinoma line 6 cells from damage by hydrogen peroxide, as reported previously for a recombinant hTrx1 expressed in Escherichia coli. This is the first report of expression of the biologically active hTrx1 protein in plant chloroplasts. This research opens up possibilities for plant-based production of hTrx1. Considering that this expression host is an edible crop plant, this transplastomic lettuce may be suitable for oral delivery of hTrx1.
authors.affiliation: Graduate School of Biological Sciences, Nara Institute of Science and Technology (NAIST), Ikoma, Nara 630-0192, Japan.
authors.forename: Soon
authors.initials: S
authors.lastname: Lim
authors.forename: Hiroki
authors.initials: H
authors.lastname: Ashida
authors.forename: Rie
authors.initials: R
authors.lastname: Watanabe
authors.forename: Koji
authors.initials: K
authors.lastname: Inai
authors.forename: Yun-Soo
authors.initials: YS
authors.lastname: Kim
authors.forename: Keiko
authors.initials: K
authors.lastname: Mukougawa
authors.forename: Hirokazu
authors.initials: H
authors.lastname: Fukuda
authors.forename: Ken-ichi
authors.initials: K
authors.lastname: Tomizawa
authors.forename: Kei-ichi
authors.initials: K
authors.lastname: Ushiyama
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Asao
authors.forename: Masahiro
authors.initials: M
authors.lastname: Tamoi
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Masutani
authors.forename: Shigeru
authors.initials: S
authors.lastname: Shigeoka
authors.forename: Junji
authors.initials: J
authors.lastname: Yodoi
authors.forename: Akiho
authors.initials: A
authors.lastname: Yokota
mesh_terms: D001483:Base Sequence; D002736:Chloroplasts / Q000378:metabolism*; D017931:DNA Primers; D006801:Humans; D018545:Lactuca / Q000378:metabolism*; D018087:Plastids; D016133:Polymerase Chain Reaction; D013879:Thioredoxins / Q000096:biosynthesis*
chemical_list: D017931:DNA Primers; D013879:Thioredoxins