FEATURE ARTICLE
Gene Chips and Functional Genomics
A new technology will allow environmental health scientists to track the expression of thousands of genes in a single, fast and easy test
Hisham Hamadeh, Cynthia Afshari
Impact of cDNA Microarrays
Microarray technology will undoubtedly have a profound impact on many avenues of biological and biomedical research, including toxicology, the main focus of our laboratory. Toxicology seeks to understand how chemicals from natural, synthetic or endogenous sources might affect humans and the environment. Here, scientists correlate gene expression patterns with biological and pathological assays to determine whether particular chemicals are harmful.
Toxicologists play an important role in defining the conditions under which chemicals may be safely employed for good causes and when a particular chemical should be avoided. Toxicologists also use gene-expression data to understand how particular toxicants affect the inner workings of the cell.
In the early days of toxicological assessment, it took months or years to establish the relation between a compound and the pathway it altered. In those days, investigators were unable to predict the key cellular players involved in the reaction of an organism to some form of environmental insult. These investigators were put in the position of essentially guessing which of the hundreds of cellular pathways might be affected. Testing these guesses to produce concrete results required the time and energy of many research teams working in concert for years, building on the information provided by previous groups. That the whole process might someday be undertaken by a group during a much shorter period of time was, just a few years ago, unimaginable.
New advances in genomics technology, such as the cDNA microarray chip, offer major shortcuts to many of our research problems. Investigators may identify important components in cellular pathways and characterize genetic footprints diagnostic for exposure to certain compounds. This technology may allow us to predict the cellular effects of new compounds—a boon not only to toxicologists but to the pharmaceutical industry as well. Use of this technology increases the efficiency of testing compounds for toxicological or pharmaceutical action and betters our understanding of which compounds to advance to later stages of clinical trials in humans.
As our use and expertise with microarray technology grows, we will have databases with expression profiles for hundreds, even thousands of genes. One will then be able to compare a new compound's expression profile to existing profiles. One might even be able to link the gene expression profile with chemical structure and predict which part of a certain molecule is responsible for the gene expression response. This technology improves our understanding of the effects of how introducing a gene into an animal might influence other biological functions.
Microarrays are certainly a giant leap into the future of performing quality biological research that holds the promise to aid in discovery of better chemicals, diagnostics and pharmaceutical compounds and ultimately, to improve the quality of life of future generations.
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