Technology
siRNA
Genome-wide RNA silencing, or RNA interference (RNAi), libraries have been developed and provide the potential to fundamentally change biological research by increasing the speed with which disease mechanisms and potential drug targets can be identified. RNAi presents many opportunities for use in gene technology and double-stranded RNA molecules have been designed to silence specific genes in humans, animals and plants. High throughput (HTP) screens of siRNA libraries have resulted in an explosion of vital information on the regulation of signaling pathways and drug targets. The opportunity to generate data by developing screens for novel targets and ideas to further the research of academicians at MD Anderson is enormous and it brings scientists one step closer to the goal of personalized medicine.
In order to perform high throughput screening (HTS) using a library of siRNAs targeting over 21,000 genes, specialized equipment is necessary to automate, miniaturize and quicken the pace of these screens. Screens are run on 384-well microplates, which contain individual wells that are approximately four millimeters wide and long and about one centimeter deep. The volumes dispensed into these wells are often very small – sometimes as small as five millionths of a liter. In order to quickly, accurately and efficiently dispense such small volumes, robots with pipetting tools and liquid dispensers have been added to the siRNA HTS laboratory. Two robots, the Biomek FX and Biomek 3000, perform very different functions from one another.
The Biomek FX has a 96-pin head which always pipettes to 96-wells and is not interchangeable. The Biomek 3000 has five interchangeable heads – some with one pin and others with eight pins – allowing us to pipette different volumes in different patterns within a 384-well plate. We also have special incubators designed specifically to hold these microplates and ensure that each one is kept at the appropriate temperature and humidity to minimize any evaporation from the wells along the edge of the plates. Finally, there are plate washers and readers that make final changes to the well volumes and take measurements from the cells to determine the effect of an siRNA to a single gene in one well. Using all of this high tech equipment, it is possible that we can perform a whole genome siRNA screen within three weeks.
Using siRNA to Perform Genome-Wide Screens (ppt)
Drosophila melanogaster as a Model Organism for Human Disease
Drosophila melanogaster has proven to be an excellent system to study human diseases for a number of reasons. The genome of Drosophila has been sequenced and about 75% of the known human disease genes have a related gene in Drosophila, so knowledge gained from experiments in Drosophila quite often can be applied to humans. Drosophila benefits from a rich genetic heritage (2006 marked the 100th anniversary of the first publications using Drosophila as a research tool) that has been supplemented in recent years by large scale gene disruption projects. Thanks to these efforts, stocks with mutations in many genes already exist.
The Drosophila community has been quick to adapt and develop new technology, such as making transgenic animals back in the 1980s, and adapting RNA interference at the turn of the century. Additionally, more than 100 years after the first Drosophila publication, the fruit fly is still appreciated as a great laboratory tool; it has a short generation time (about two weeks) and is small and easy and inexpensive to grow.
We use Drosophila as a model organism to ask specific genetic questions related to human cancer. We complement our research in Drosophila with follow-up experiments in mammalian tissue culture. Combining two systems, mammalian cells for mimicking human disease and Drosophila, to answer genetic questions allows us to capitalize on the strengths of both that will, with hope, lead to the identification of novel genes relevant to human cancer.
Xenogen IVIS® Lumina Imaging System
The IVIS® Lumina Imaging System allows the performance of real-time imaging in mice or in tissue culture cells using fluorescent and/or bioluminescent reporters. We are conducting in vivo experiments to monitor and measure activity of light production from xenografts using luciferin.
Nespresso™ Professional
A "natural products extractor and condenser". In layman's terms: it makes our morning espressos, cappucinos and coffee -- and generally keeps the lab going.