Why do OX5034 GM mosquitos require the presence of tetracycline to survive? What does the drug do in this case?
They don't go into any detail on the sites you link to and I don't have time to look into patents, but from the context it sounds like they may be using a tetracycline repressible promoter. This is often referred to as a Tet-Off promoter.
The core elements of these promoters were discovered in the bacterium Escherichia coli1 and several variations have been developed. These types of promoters work in organisms from bacteria to yeast to mammals1-3.
References
1: Gossen, M., &amp; Bujard, H. (1992). Tight control of gene expression in mammalian cells by tetracycline-responsive promoters. Proceedings of the National Academy of Sciences, 89(12), 5547-5551.
2: Baron, U., &amp; Bujard, H. (2000). Tet repressor-based system for regulated gene expression in eukaryotic cells: principles and advances. Methods in enzymology, 327, 401-421.
3: Orth, P., Schnappinger, D., Hillen, W., Saenger, W., &amp; Hinrichs, W. (2000). Structural basis of gene regulation by the tetracycline inducible Tet repressor–operator system. Nature structural biology, 7(3), 215-219.