Expression of a synthetic cholera toxin B subunit in tobacco using ubiquitin promoter and bar gene as a selectable marker.
A protocol has been developed to produce a cholera toxin B subunit (CTB) in tobacco tolerant to the herbicide phosphinothricin (PPT) by means of in vitro selection. The synthetic CTB subunit gene was altered to modify the codon usage to that of tobacco plant genes. The gene was then cloned into a plant expression vector and was under the control of the ubiquitin promoter and transformed into tobacco plants by Agrobacterium-mediated transformation. Transgenic plantlets were selected in a medium supplemented with 5 mg/L PPT. Polymerase chain reaction analysis confirmed stable integration of the synthetic CTB gene into a chromosomal DNA. A high level of CTB (1.8% of total soluble protein) was expressed in transgenic plants, which was 18-fold higher than that under the control of the expressed CaMV 35S promoter with native gene. The transgenic plants when transferred to a greenhouse proved to be resistant to 2% PPT.
Kang
Tae-Jin
TJ
Team of Research & Development, Jeonbuk Bioindustry Development Institute, Jeonju 561-360, South Korea.
Kim
Bang-Geul
BG
Yang
Ji-Yeon
JY
Yang
Moon-Sik
MS
D002772:Cholera Toxin / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D015870:Gene Expression; D017343:Genes, Plant; D005819:Genetic Markers; D005822:Genetic Vectors; D066298:In Vitro Techniques; D030821:Plants, Genetically Modified; D011401:Promoter Regions, Genetic; D012231:Rhizobium / Q000235:genetics; D012641:Selection, Genetic; D014026:Nicotiana / Q000235:genetics / Q000378:metabolism*; D014170:Transformation, Genetic; D019076:Transgenes; D025801:Ubiquitin / Q000235:genetics
D005819:Genetic Markers; D025801:Ubiquitin; D002772:Cholera Toxin