Maize line Bt11 was genetically modified to contain two novel
genes, cry1Ab and pat, for insect and herbicide tolerance
respectively. Both genes were introduced into a maize line by
particle acceleration (biolistic) transformation.
Information on the inserted DNA sequences:
- 35S promoters derived from cauliflower mosaic virus (CaMV) and
35S-1 originated from the CM1841 isolate of CaMV as a 500 Ddel to
Ddel fragment, subsequently converted to Sacl sites and 35S-2
originated from the Cabb-S strain of CaMV as a n Alul to Ddel
fragments (ca 425bp), whose ends were subsequently modified.
- introns derived from the maize alcohol dehydrogenase 1S gene and
were used to enhance heterologous gene expression.
- Btk gene which is an altered version of the full length cry1A(b)
gene of Bacillus thuringiensis var kurstaki HD-1. The Btk was
obtained as a 1.8kb Nco-Bg/ll fragment. The truncated Btk protein
is identical to the N-terminal 615 amino acids of the native Btk
protein of 1155 amino acids.
- pat gene (phosphinotricin acetyl transferase) cloned from the
soil microorganism, Streptomyces viridochromogenes strain
Tu494. Alteration did not result in any amino acid sequence
changes.
- nos terminator consisting of 423-678 of the nopaline synthase
gene of Agrobacterium tumefaciens plus added restriction
sites.
Vector information
Plasmid pZO1502 is the vector used for the transformation of Bt
maize. This is a derivative of plasmid pUC18. The plasmid has
a molecular weight of 2.7 kb and contains the following
sequences:
- the prokaryotic gene bla (also called ampR) under a procaryotic
promoter encoding β-lactamase, which confers resistance to
ampicillin; it is used as a bacterial selectable marker;
- the gene lac Z, encoding a portion of a β-galactosidase, this
gene is not functional;
- the pUC origin of replication derived from the plasmid pBR 322
carrying a mutation.
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