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[SANET-MG] death domains ,VIP3A gene and cherry picking
February 11, 2005
Prof. Joe Cummins
?Death domains and the VIP3A insect toxin gene?
Cell death is an important feature of growth and differentiation in all multi
cellular organisms. In 1972 the term ?apoptosis? was used to describe the
cell changes associated with programmed cell suicide. The death program
includes cell membrane blebbing, cells shrinkage and characteristic patterns
of DNA fragmentation and finally disassembly of the cell. Each cell is
equipped with regulatory proteins bearing ?death domains? There is a common
fundamental design to the death domains and their regulatory circuitry in
animals and plants. The area of programmed death and anti-death signaling has
grown very large and its implication in cancer care, immunity and even pest
control are being explored. Numerous reviews of the subject are available,
three current reviews are included as reference 1,2, and 3.
The Bacillus thuringiensis (Bt) toxin genes currently employed in commercial
crops . are all members of a class of toxin proteins that accumulate , as
crystals , in stationary stage bacteria (bacteria that have completed their
growth cycle) these genes are designated Cry followed by numbers and letters
that indicate there origin and specificity . These toxins all create pores in
the insect cell membranes leading to osmotic lysis of the cells. Another kind
of Bt toxin, VIP group of toxins are produced in vegetative cells , the genes
are designated VIP followed by numbers and letters related to their origin and
specificity. According to US Patents 6,291,156 (4) and 6,429,360 (5) from
Syngenta Corporation provided compelling evidence that the Bt toxin VIP3A
toxin contained putative death domains and the patents provided clear evidence
that the toxin induced apoptosis in insect cells. Earlier reports from the
United States Department of Agriculture (USDA) laboratory In Beltsville ,
Maryland showed that crude preparations of mixed Bt toxins induced apoptosis
in insect larvae. Agents that induce apoptosis may provide powerful pest
control sources , but, such agents require care in evaluating their impact
on non-target animals and plants (8).
A research group from Syngenta published a study showing that along with
apoptosis VIP3A supported pore formation in the membrane as an inherent
property. The research report noted that the pore formation mechanism was not
mutually exclusive with apoptosis. However, the researchers believed that
pore formation was the main basis for toxicity(9).
In 2005 Syngenta petitioned for non-regulated status of cotton event COT102, a
cotton variety resistant to Lepidopteran pests because it was modified with a
synthetic gene approximation of VIP3A(a) (10). The USDA/APHIS Environmental
Assessment of transgenic cotton event COT102 accompanied the petition(11).
Surprisingly both the petition and the environment assessment appear to have
ignored the aspect of apoptosis and death domains in their extensive reviews.
Even though USDA researchers had determined that crude Bt toxin preparation
induced apoptosis the formal reviews and petition appear to have completely
side stepped the implications of death domains and apoptosis for non-target
animals and plants.
The basis of science reporting has previously been that experiments should be
reported fully and truthfully. USDA/APHIS appears to have unilaterally amended
the science principle to a process more like cherry picking. Only plump, ripe,
palatable results need be considered.
The company submission was posed as a docket for public consultation as shown
04-51-1 APHIS-2005-0007 Syngenta Seeds, Inc.; Availability of Petition and
Environmental Assessment for Determination of Nonregulated Status for Cotton
Genetically Engineered for Insect Resistance 01-28-2005 General Docket
04-51-2 Syngenta Petition 03-155-01p for Determination of Nonregulated Status
for Lepidopteran Resistant Event COT102
I wish to urge others to look at the documents posted with Syngenta Petition
03-28-2005 and to submit a comment prior to the closing dates for comments :
03-29-2005 . The main question is ?have adequate safety tests been done to
allow exposure to the toxin and its gene in fiber, food and feed?? I do not
believe that the studies are at all adequate.
1.Bhardwa,A. and Aggarwal,B. Receptor-mediated choreopgraphy of life and death
2003 Journal of Clinical immunology 23, 317-32
and Kitsis,R. Inhibition of Both the Extrinsic and Intrinsic Death Pathways
through Nonhomotypic Death-Fold Interaction 2004 Molecular Cell 15,901-12
3. Barnhart,B, Lee,J,Alappat,E.and Peter,M. The death effector domain protein
family 2003 Oncogene 22,8634-44
4.Estruch,J. and Yu,C. Plant Pest Control 2001 US Patent 6,291,156
5. Estruch J, Warren G, Desai N, Kozeil M, and Nye G. Plant Pest Control.2001 US
6. Loeb, M, Martin,P, Narang, N, Hakim, R, Goto S. and Takeda, M. Control of
life, death, and differentiation in cultured midgut cells of the lepidopteran,
Heliothis virescens 2001 In Vitro Cell Dev Biol Anim. 37,348-52
7. Loeb,M,Hakim,R,Martin,P,Narang,N,GotoS. and Takeda,M. Apoptosis in Cultured
Midgut Cells From Heliothis virescens Larvae Exposed to Various Conditions 2000
Archives of Insect Biochemistry and Physiology 45:12?23
8. Cummins,J. New GM toxin looms over our food 2003
http://www.i-sis.org.uk/full/NGMTLOOFFull.phpISIS Press Release 02/12/03
9. Lee,M,Walters,F,Hart,H,Palekar,N. and Chen,J. The Mode of Action of the
Bacillus thuringiensis Vegetative Insecticidal Protein Vip3A Differs from That
of Cry1Ab Endotoxin 2003 Applied and Environmental Microbiology 69,4648-57
10.Artim.L. Application for determination of non-regulated status for
lepidopteran insect protected VIP3A cotton transformation event COT102 2005
11.USDA/APHIS Environment Assessment Syngenta Petition 03-155-01p for
determination of noinregulated status for lepidopteran resistant event COT102
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