Questions and answers about EntoEngine strain 2

EntoEngine strain 1 was modified with a gene to express a bovine (cow) growth factor protein, whereas EntoEngine strain 2 is modified with a gene to express a human growth factor protein. In both strains, the growth factor genes were inserted in random locations in the fruit fly genome. Slight differences in the methods used in the construction of the two strains resulted in all the adult fruit flies of strain 1 possessing curly wings, reducing their ability to fly. In contrast, approximately 1/3 of strain 2 adult fruit flies develop straight wings with the ability to fly, while 2/3 have curly wings with reduced ability to fly.

The manufacture of EntoEngine strain 2 flies occurs in the same facility under similar physical containment measures as strain 1, which is designed to prevent any flies from escaping into the natural environment. For EntoEngine strain 2, there is an additional containment measure of separating and discarding all adult flies with straight wings (that contain the human growth factor gene) prior to propagation.

In the event of accidental release from the facility, survival of EntoEngine strain 2 flies in the environment is highly unlikely. It is also highly unlikely that they would reproduce with other fruit flies and disperse outside of the facility because they are severely inbred and weakened by their genetic modifications. There is no evidence to suggest that their genetic material could combine with flies outside of the facility nor alter the biodiversity of wild fruit fly populations. Furthermore, the facility was designed in accordance with regulatory guidelines including The National Institutes of Health Arthropod Containment Guidelines and The Canadian Food Inspection Agency Containment Standards for Facilities Handling Plant Pests, in efforts to ensure appropriate containment and preventative release measures.

Under subsection 106(8) of the Canadian Environmental Protection Act, 1999 (the Act), a notifier may submit a request to waive a requirement for any of the prescribed information of a notification schedule. Similar to EntoEngine strain 1, the notifier requested a waiver for a test to determine the organism’s toxicity under subsection 106(8)(a) of the Act, on the basis that the information was not needed to determine whether the living organism is toxic or capable of becoming toxic. Drosophila melanogaster has a long history of safe use as a research and development organism, does not produce toxins and there is no evidence of adverse environmental impacts. The addition of the transgene to produce a human growth factor is not expected to alter the potential toxicity of EntoEngine strain 2 and therefore the waiver was granted.

Risk assessments for both EntoEngine fruit fly strain 1 and EntoEngine fruit fly strain 2 concluded that there is a low risk to the environment and human health. The species has a long history of safe use with no documented reports of adverse effects to the environment or human health.

Both recombinant bovine FGF2 and recombinant human FGF2 are produced in their respective strains as a single, non-glycosylated, polypeptide chain containing 155 amino acids, and each has a molecular mass of 17.3 kDa. Both the bovine growth factor protein and the human growth factor protein are nontoxic, similar in structure and function, and used to grow different types of cell culture lines.