A Gene-Shuffled Glyphosate Acetyltransferase Protein from Bacillus licheniformis (GAT4601) Shows No Evidence of Allergenicity or Toxicity

Abstract

The glyphosate acetyltransferase (gat) gene from Bacillus licheniformis was subjected to multiple rounds of gene shuffling to optimize kinetics of corresponding GAT proteins to acetylate the herbicide active ingredient glyphosate. Genetically modified soybeans expressing the gat4601 gene (356043 soybeans) are tolerant to the application of glyphosate. The current manuscript reports the outcome of the allergenicity and toxicity assessment for the GAT4601 protein. Bioinformatic comparison of the amino acid sequence of GAT4601 did not identify similarities to known allergenic or toxic proteins. In vitro studies conducted with heterologously produced GAT4601 protein demonstrated that it was rapidly degraded in simulated gastric fluid containing pepsin (< 30 s) and in simulated intestinal fluid containing pancreatin (< 2 min) and completely inactivated at temperatures above 56 degrees C. The GAT4601 protein expressed in planta is not glycosylated and similar protein profiles were observed in flour extracts from 356043 soybeans and nontransgenic near isoline comparator soybeans (Jack) using serum from soy allergic persons. No evidence of adverse effects was observed in mice following acute oral exposure to 2000 mg/kg of GAT4601 protein or in a repeated dose dietary exposure study at doses of 800-1000 mg/kg/day. This comprehensive assessment demonstrates that the GAT4601 protein does not present a risk for adverse effects in humans when used in the context of agricultural biotechnology.

Do genetically modified crops affect animal reproduction? A review of the ongoing debate

“…Therefore, in a short-term feeding study, there were no statistically significant differences in the testis weight compared with rats fed non-GM soybeans (Delaney et al, 2008a). Moreover, no microscopic pathology was observed in testes of Cry34Ab1 or Cry35Ab1 protein-treatment groups for 28 days, even at a repeated high dose 1000-fold .…”

“…At present, many groups used a short-term (not .1 month) feeding animal model to evaluate safety of GM crops. When feeding different GM crops to mice, no adverse effects were observed in the ovaries fed for 27 days by a GM crop 356043 soybeans contained glyphosate acetyltransferase protein, GAT4601 protein; Delaney et al, 2008a). Moreover, no microscopic pathology was observed in vagina of animals treated with Cry34Ab1 or Cry35Ab1 proteins for 28 days, even at repeated high dose (1000-fold greater than the highest estimate of human exposure based on the concentrations of these proteins expressed in 59 122 maize grain; Juberg et al, 2009).…”

Expression of The Human Acidic Fibroblast Growth Factor in Transgenic Tomato and Safety Assessment of Transgenic Lines

“…Similar assessments are made for recombinant proteins and products of genes used as selectable markers in genetic transformation of soybeans (15,42).…”

“…The first series of media contained different concentrations of glucose (0, 1, 2 and 5 g/l) and the second series contained mannose (10,12,15,20 and 30 g/l) along with 5 g/l glucose.…”

Immunoproteomic and Two-Dimensional Difference Gel Electrophoresis Analysis of Arabidopsis Dehydration Response Element-Binding Protein 1A (DREB1A)-Transgenic Potato

“…3,4) Immunoproteomic analysis of allergens with sera from allergic patients is a useful method for comprehensively comparing unknown allergens as well as known allergens in extracts of foods derived from transgenic organisms. Previously, we reported application of the immunoproteome to assess allergenicities of GH-1 (growth hormone 1)-transgenic amago salmon 5) and enhanced green fluorescent protein (EGFP)-transgenic chicken meat.…”