RESUMEN
Glucagon-like peptide-1 (7-36) amide (GLP-1) is the most potent physiological insulinotropic hormone in humans. We produced large amounts of a GLP-1 analogue, [Ser8, Gln26, Asp34]-GLP-1, which is resistant to trypsin-digestion, as part of a chimeric rice seed storage protein, a 26 kDa globulin, in genetically modified rice seeds. Junction sites between GLP-1 analogue and globulin were replaced by tryptic cleavage sites. The highest level of GLP-1 analogue accumulation was approximately 20-50 microg per seed. We found that GLP-1 analogue derived from trypsin-digested genetically modified rice seeds stimulated insulin secretion from a mouse pancreatic beta-cell line, MIN6.
Asunto(s)
Glucagón/metabolismo , Glucagón/farmacología , Insulina/metabolismo , Islotes Pancreáticos/efectos de los fármacos , Islotes Pancreáticos/metabolismo , Oryza/metabolismo , Fragmentos de Péptidos/metabolismo , Fragmentos de Péptidos/farmacología , Precursores de Proteínas/metabolismo , Precursores de Proteínas/farmacología , Semillas/metabolismo , Animales , Secuencia de Bases , Línea Celular , Vectores Genéticos/genética , Globulinas/genética , Globulinas/metabolismo , Glucagón/genética , Péptido 1 Similar al Glucagón , Secreción de Insulina , Islotes Pancreáticos/citología , Ratones , Oryza/genética , Fragmentos de Péptidos/genética , Precursores de Proteínas/genética , Proteínas Recombinantes de Fusión/genética , Proteínas Recombinantes de Fusión/metabolismo , Proteínas Recombinantes de Fusión/farmacología , Semillas/genéticaRESUMEN
Conjugated linoleic acid (CLA) has anti-carcinogenic and anti-atherosclerosis activity, and modulatory effects on the immune system and lipid metabolism. To produce a transgenic rice plant that can accumulate CLA, a linoleate isomerase gene that can convert linoleic acid to trans-10, cis-12 CLA was introduced and expressed under the control of seed-specific promoters from the oleosin and globulin genes. The fatty acid composition of the transgenic rice grain was analyzed by gas chromatography. Although there was no clear difference in the fatty acid composition between seeds from transformed versus untransformed plants, a peak of trans-10, cis-12 CLA methyl ester, which was not present in seeds from untransformed plants, was found in transformed plants. The trans-10, cis-12 CLA comprised an average of 1.3% (w/w) of the total fatty acids in seeds carrying the oleosin promoter in comparison to 0.01% (w/w) in seeds carrying the globulin promoter. In addition, approximately 70 and 28% of the total amount of the CLA isomer were present in the triacylglycerol and free fatty acid fractions, respectively. These results demonstrate the ability to produce fatty acid components of vegetable oils with novel physiological activities in crops.