<p style="text-align: justify;">Maize line MON 863 was produced using recombinant-DNA techniques to express the <i>cry3Bb1</i> gene encoding a Coleopteran-specific insecticidal protein from <i>Bacillus thuringiensis</i> (subsp. <i>kumamotoensis</i>) in order to control infestation with corn root worm (CRW; <i>Diabrotica</i> <i>sp</i>.). This gene was introduced into the publicly available inbred line, A634, by particle acceleration (biolistic) transformation.</p>

<p style="text-align: justify;">The <i>cry3Bb1</i> gene encodes the insect control protein Cry3Bb1, a delta-endotoxin. Cry proteins, of which Cry3Bb1 is only one, act by selectively binding to specific sites localized on the lining of the midgut of susceptible insect species. Following binding, pores are formed that disrupt midgut ion flow, causing gut paralysis and eventual death due to bacterial sepsis. Cry3Bb1 is lethal only when eaten by Coleopteran species, including corn root worm, and its specificity of action is directly attributable to the presence of specific binding sites in the target insects. There are no binding sites for the delta-endotoxins of <i>B. thuringiensis</i> on the surface of mammalian intestinal cells, therefore, livestock animals and humans are not susceptible to these proteins.</p>

<p style="text-align: justify;">An antibiotic resistance marker gene (<i>neo</i>; synonym <i>nptII</i>) encoding the enzyme neomycin phosphotransferase II (NPTII), which inactivates aminoglycoside antibiotics such as kanamycin and neomycin, was also introduced into the genome of this transgenic maize. This gene was derived from a bacterial transposon (Tn5 transposable element from <i>Escherichia coli</i>) and was included as a selectable marker to identify transformed plants during tissue culture regeneration and multiplication. The expression of the <i>nptII</i> gene in these plants has no agronomic significance and the safety of the NPTII enzyme as a food additive was evaluated by the United States Food and Drug Administration in 1994 (US FDA, 1994).</p>
