The similarities of bar and pat gene products make them equally applicable for plant engineers

Abstract

The bar and pat genes, isolated from different Streptomyces species, both encode a phosphinothricin acetyltransferase (PAT) and are widely applied in plant genetic engineering. The genes were expressed in Escherichia coli and the corresponding proteins were purified and used for functional and structural comparison. Both proteins are homodimers regardless of whether they are expressed in microorganisms or in plants. They have comparable molecular weights and show immuno-cross-reactivity to their respective polyclonal antisera. The enzymes have a similar substrate affinity towards L-phosphinothricin and do not acetylate any of the other L-amino acids tested. In model digestion experiments using simulated human gastric fluids, their enzymatic activity is decreased within seconds, accompanied by a rapid and complete breakdown of both proteins. These data demonstrate the structural and functional equivalence of the PAT proteins, which is also reflected in the comparable performance of transgenic plants carrying the bar or pat gene.

The pleiotropic effects of thebargene and glufosinate on theArabidopsistranscriptome

“…Ammonium is generated in a variety of metabolic processes and serves as the nitrogen donor for the biosynthesis of all nitrogenous organic compounds needed for plant growth and development (Crawford and Arst, 1993;DanielVedele et al ., 1998). The mechanism of L -PPT toxicity is believed to involve ammonia accumulation to phytotoxic levels, followed by the impairment of photosynthesis causing plant death (Wendler et al ., 1990;Wehrmann et al ., 1996;Dan Hess, 2000).…”

Four new SYBR®Green qPCR screening methods for the detection of Roundup Ready®, LibertyLink®, and CryIAb traits in genetically modified products

“…The major commercial transgenic HT crops to date incorporate two different classes of genes: the bacterial phosphinotricin-N-acetyltransferases from Streptomyces viridochromogenes (pat) and from Streptomyces hygroscopicus (bar) [2] and the 5-enolpyruvylshikimate-3-phosphate synthase (epsps) from Agrobacterium tumefasciens strain CP4 or from plant origin (in casu petunia) [3,4]. Both classes of HT genes have been engineered into commercially grown GM crops [5].…”

‘Ξένο’ DNA Από Τη Χορηγούμενη Τροφή Στον Οργανισμό Των Ζώων Και Αξιολόγηση Της Ασφάλειας Των Γενετικώς Τροποποιημένων Ζωοτροφών

“…Όσον αφορά στην τύχη των καινοφανών πρωτεϊνών, δοκιμές in vitro έχουν δείξει ότι, με την εξαίρεση γενετικώς τροποποιημένων γεωργικών προϊόντων, στα οποία είχε εισαχθεί γονίδιο για την έκφραση βακτηριακής λεκτίνης, η οποία έχει αποδειχθεί πολύ ανθεκτική στην πρωτεόλυση, τα πρωτεϊνικά προϊόντα των διαγονιδίων που εισήχθησαν σε εμπορικές καλλιέργειες της εποχής εκείνης, αποδομήθηκαν ταχέως όπως άλλες πρωτεΐνες της τροφής (Harrison et al 1996, Wehrmann et al 1996. Μολαταύτα, πιστεύουμε ότι απαιτούνται περισσότερες in vivo μελέτες για τη διερεύνηση της αποδόμησης καινοφανών πρωτεϊνών.…”