Biology Reference
In-Depth Information
A second approach involved associating or fusing protein domains from different
meganucleases, which results in chimeric meganucleases with a new recognition
site composed of a half-site of meganuclease A and a half-site of B. These two
approaches can be combined to increase the possibility of creating new enzymes,
while maintaining a high degree of efficacy and specificity.
It has been suggested that these selfish elements could be used to genetically
manipulate natural populations of pest insects by driving the homing endonu-
clease gene through the population even when the insert may have deleterious
effects on the host (
Deredec et al. 2008, Chan et al. 2011
). A homing endonucle-
ase was inserted into
D. melanogaster
and high rates of homing were achieved
within spermatogonia and in the female germ line (
Chan et al. 2011
).
9.19.6 Cell-Penetrating Peptides
Large molecules, such as proteins, DNA or RNA, cannot penetrate cell mem-
branes easily. However, cell-penetrating peptides are a group of short peptides
that can cross the cell membrane and could potentially deliver genes into living
cells (
Chen et al. 2012
).
Chen et al. (2012)
showed that three arginine-rich cell-
penetrating peptides could form stable complexes with plasmid DNA and enter
insect cells in cell culture. The transferred plasmids containing green fluorescent
and red fluorescent protein genes were expressed. This gene-delivery method
resulted in a low level of cell mortality (7-16%), suggesting the peptides are not
toxic and might be useful for developing transgenic arthropods.
9.19.7 Nanotechnology Approaches
The definition of nanotechnology is difficult to resolve because it involves many
techniques and has potential for use in many applications, including plant bio-
technology, electronics, energy, and medicine (
Nair et al. 2010
). Furthermore,
the field is changing rapidly and evolving in its potential techniques and appli-
cations. However, nanotechnology can deliver macromolecules in a targeted
manner and has been used to deliver DNA into plants and insects (
Nair et al.
2010, Zhang et al. 2010
). To date, the risk issues and regulatory issues associated
with nanotechnology remain to be resolved. Nanoparticles can be transported
in the environment and can bioaccumulate in the food chain.
RNAi and nanoparticles were combined to silence chitin synthase genes in
Anopheles gambiae
(
Zhang et al. 2010
). The double-stranded RNA molecules
(RNAi) were included in nanoparticles of chitosan, a nontoxic and biodegrad-
able polymer, and the nanoparticles were fed to larvae. The results suggested
that RNAi in
An. gambiae
is systemic (unlike the situation in
D. melanogaster
)
