A visible marker for antisense mRNA expression in plants: inhibition of chlorophyll synthesis with a glutamate-1-semialdehyde aminotransferase antisense gene.
Glutamate 1-semialdehyde aminotransferase [(S)-4-amino-5-oxopentanoate 4,5-aminomutase, EC 5.4.3.8] catalyzes the last step in the conversion of glutamate to delta-aminolevulinate of which eight molecules are needed to synthesize a chlorophyll molecule. Two full-length cDNA clones that probably represent the homeologous Gsa genes of the two tobacco (Nicotiana tabacum) genomes have been isolated. The deduced amino acid sequences of the 468-residue-long precursor polypeptides differ by 10 amino acids. The cDNA sequence of isoenzyme 2 was inserted in reverse orientation under the control of a cauliflower mosaic virus 35S promoter derivative in an expression vector and was introduced by Agrobacterium-mediated transformation into tobacco plants. Antisense gene expression decreased the steady-state mRNA level of glutamate 1-semialdehyde aminotransferase, the translation of the enzyme, and chlorophyll synthesis. Remarkably, partial or complete suppression of the aminotransferase mimics in tobacco a wide variety of chlorophyll variegation patterns caused by nuclear or organelle gene mutations in different higher plants. The antisense gene is inherited as a dominant marker.
Höfgen
R
R
Schering AG, Pflanzenschutzforschung, Berlin, Germany.
Axelsen
K B
KB
Kannangara
C G
CG
Schüttke
I
I
Pohlenz
H D
HD
Willmitzer
L
L
Grimm
B
B
von Wettstein
D
D
D000595:Amino Acid Sequence; D002734:Chlorophyll / Q000096:biosynthesis; D003001:Cloning, Molecular; D015870:Gene Expression; D017343:Genes, Plant; D005819:Genetic Markers; D005822:Genetic Vectors; D019751:Intramolecular Transferases; D007535:Isomerases / Q000235:genetics; D008969:Molecular Sequence Data; D010641:Phenotype; D030821:Plants, Genetically Modified; D010947:Plants, Toxic; D016372:RNA, Antisense / Q000235:genetics*; D012333:RNA, Messenger / Q000235:genetics*; D014026:Nicotiana / Q000235:genetics* / Q000378:metabolism; D014170:Transformation, Genetic
D005819:Genetic Markers; D016372:RNA, Antisense; D012333:RNA, Messenger; D002734:Chlorophyll; D007535:Isomerases; D019751:Intramolecular Transferases; C061049:glutamate-1-semialdehyde 2,1-aminomutase