Monarch Butterflies and Bt corn--Table 2

The following table shows why Bt 176 corn pollen is toxic to butterfly larvae. Bt 176 contains a pollen-specific promoter that is very effective in causing Bt protein to be produced in the corn pollen.


Bt event promoter element(s)

amount of Bt protein in pollen*

Bt 176 1) A promoter derived from a pollen-specific protein kinase in maize, linked to the Bt CryIA(b) gene. This promoter causes the Bt protein to be produced in the pollen.
2) A promoter derived from phosphoenolpyruvate carboxylase in maize, linked to the Bt CryIA(b) gene. This promoter causes the Bt protein to be produced in green tissues such as stems and leaves. There is little or no Bt protein produced in the kernels.
Specific information on the origin of these promoters is available at http://www.aphis.usda.gov/biotech/
dec_docs/9431901p_det.HTM
. Scroll down to section IV. Analysis of the properties of event 176 corn, then down to subheading A on the introduced genes and their products.
1.1 to 7.1 micrograms per gram of pollen
Bt 11 The promoter from the cauliflower mosaic virus 35S gene, linked to the Bt CryIA(b) gene. This promoter causes the Bt protein to be produced in all tissues of the plant. 0.09 micrograms per gram of pollen
MON810 The promoter from the cauliflower mosaic virus 35S gene, linked to the Bt CryIA(b) gene. This promoter causes the Bt protein to be produced in all tissues of the plant. 0.09 micrograms per gram of pollen

* This information is from Sears et al., 2001.

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