Insulated piggyBac vectors for insect transgenesis.
BACKGROUND
Germ-line transformation of insects is now a widely used method for analyzing gene function and for the development of genetically modified strains suitable for pest control programs. The most widely used transposable element for the germ-line transformation of insects is piggyBac. The site of integration of the transgene can influence gene expression due to the effects of nearby transcription enhancers or silent heterochromatic regions. Position effects can be minimized by flanking a transgene with insulator elements. The scs/scs' and gypsy insulators from Drosophila melanogaster as well as the chicken beta-globin HS4 insulator function in both Drosophila and mammalian cells.


RESULTS
To minimize position effects we have created a set of piggyBac transformation vectors that contain either the scs/scs', gypsy or chicken beta-globin HS4 insulators. The vectors contain either fluorescent protein or eye color marker genes and have been successfully used for germ-line transformation of Drosophila melanogaster. A set of the scs/scs' vectors contains the coral reef fluorescent protein marker genes AmCyan, ZsGreen and DsRed that have not been optimized for translation in human cells. These marker genes are controlled by a combined GMR-3xP3 enhancer/promoter that gives particularly strong expression in the eyes. This is also the first report of the use of the ZsGreen and AmCyan reef fluorescent proteins as transformation markers in insects.


CONCLUSIONS
The insulated piggyBac vectors should protect transgenes against position effects and thus facilitate fine control of gene expression in a wide spectrum of insect species. These vectors may also be used for transgenesis in other invertebrate species.
Sarkar
Abhimanyu
A
Centre for Functional Genomics, Institute of Molecular BioSciences, Massey University, Private Bag 11222, Palmerston North, New Zealand. A.Sarkar@massey.ac.nz
Atapattu
Asela
A
Belikoff
Esther J
EJ
Heinrich
Jörg C
JC
Li
Xuelei
X
Horn
Carsten
C
Wimmer
Ernst A
EA
Scott
Maxwell J
MJ
D000818:Animals; D030801:Animals, Genetically Modified / Q000235:genetics*; D004251:DNA Transposable Elements / Q000235:genetics; D029721:Drosophila Proteins / Q000235:genetics*; D004331:Drosophila melanogaster / Q000235:genetics*; D005818:Genetic Engineering / Q000379:methods*; D005822:Genetic Vectors / Q000235:genetics*; D007915:Lepidoptera / Q000235:genetics*; D014170:Transformation, Genetic / Q000235:genetics*
D004251:DNA Transposable Elements; D029721:Drosophila Proteins