The ability to specify the expression levels of exogenous genes inserted in the 
genomes of transgenic animals is critical for the success of a wide variety of 
experimental manipulations. Protein production can be regulated at the level of 
transcription, mRNA transport, mRNA half-life, or translation efficiency. In 
this report, we show that several well-characterized sequence elements derived 
from plant and insect viruses are able to function in Drosophila to increase the 
apparent translational efficiency of mRNAs by as much as 20-fold. These 
increases render expression levels sufficient for genetic constructs previously 
requiring multiple copies to be effective in single copy, including constructs 
expressing the temperature-sensitive inactivator of neuronal function 
Shibire(ts1), and for the use of cytoplasmic GFP to image the fine processes of 
neurons.