Let’s see. What do we have so far?
Great genomic resources? Check.
Great gene vectors? Check.
Great genome modification technologies? Check.
Effective insect genetic technology delivery systems for somatic and germ cells? Not so much, unfortunately.
Gene, transgene and RNA delivery remains a major bottleneck in the development and adoption of insect genetic technologies for many insect species. Currently, micro-injection is just about the only effective means by which one can deliver current genetic technologies to insect cells in vivo.
This can be a serious limitation and creative solutions are needed since it is clear that many important insect species either do not produce eggs, produce them rarely or produce eggs that are inaccessible.
Gene delivery problems are also common in other fields of biology and it is worth watching the various solutions that emerge from seemingly unrelated systems. It is very likely that some of these technologies and approaches will be helpful to insect biologists..
Xiong et al (2014) describe their solution to delivering DNA and RNA to hair cells of the mammalian inner ear using a method they call “Injectoporation”, a combination of micro-injection and electroporation.
Xiong et al (2014) work with explanted inner ear tissue maintained in vitro and are able to inject DNA into the region of the hair cells of interest while simultaneously pulsing the tissue with electricity, 60 volts for 15 milliseconds at 1-second intervals.
How injectoporation will be directly useful to those wishing to deliver genetic technologies to cells of interesting and significant insects is not immediately obvious, but injectoporation is a great example of creative technology development. Significantly, electroporation has been used in insect systems before, most recently by Ando and Fujiwara (2013) and Matsumoto et al. (2013) for introducing DNA into insect cells in vivo,. Both of these reports describe interesting and creative ways to use electroporation technology for gene delivery in vivo. For a brief bibliography of other examples of elecctroporation being applied to insects, see below.
Here is a short bibliography of electroporation-related applications to insects:
Matsumoto CS, Shidara H, Matsuda K, Nakamura T, Mito T, Matsumoto Y, Oka K, Ogawa H (2013) Targeted gene delivery in the cricket brain, using in vivo electroporation. J Insect Physiol 59: 1235-1241 10.1016/j.jinsphys.2013.10.001
Fujiwara T, Kazawa T, Haupt SS, Fukushima R, Kanzaki R (2008) Ca2+ imaging of single neurons marked by local electroporation in antennal lobes of insects. Comparative Biochemistry and Physiology B-Biochemistry & Molecular Biology 151: 447-447 10.1016/j.cbpb.2008.09.071
Gonzalez-Estevez C, Momose T, Gehring WJ, Salo E (2003) Transgenic planarian lines obtained by electroporation using transposon-derived vectors and an eye-specific GFP marker. Proc Natl Acad Sci U S A 100: 14046-14051 10.1073/pnas.2335980100
Hughes KJ, Narang SK, Leopold RA, Johnson OA, DeVault JD (1997) Electroporation as an alternative to microinjection of plasmid DNA into bollworm (Lepidoptera: Noctuidae) embryos. Ann Entomol Soc Am 90: 107-113