Sainthood is probably not in the cards for most life scientists. And while some accomplishments may seem miraculous, discovering transcription factors and their role can be attributed to the dedication and diligence of many researchers. Now, these DNA-binding gene expression regulators are more easily uncovered with the numerous kits, reagents, and assays currently on the market.
Researchers have been working to elucidate the mechanism of transcription for decades. In a 1969 issue of Nature, Roeder described the identification of three types of RNA polymerases. Before long, he was well into pursuing his goal of replicating transcription in a cell-free system. Roeder soon found that purified RNA polymerases weren’t able to initiate transcription at the start sites. Thus began the search for the components that allow transcription to initiate accurately.
Eventually, Roeder and many colleagues showed that transcription factors were necessary not only for initiation, but also for inhibiting, promoting, or enhancing transcription. These proteins regulate gene expression through interaction with specific regions along the chromosome. The DNA-binding domains of the transcription factors recognize sequences that have since been categorized into zinc fingers, helix-turn-helix, leucine zipper, helix-loop-helix, and high mobility groups. An activator domain facilitates transcription by interacting with the RNA polymerase and other necessary components. In addition to further elucidating this mechanism, researchers are also trying to correlate transcription factors with actual physiological phenomena.
“Important processes … are increasingly being demonstrated to be dependent on DNA binding transcription factors,” wrote David S. Latchman in his book, Transcription Factors: A Practical Approach (Oxford University Press, June 1999).
This is occurring through the use of several methods, including the DNA mobility shift assay and the DNaseI footprinting and methylation interference techniques, which assist in pinpointing the activity and presence of transcription factors. Or, straightforward study of the “biochemical characteristics of the protein can be studied, allowing determination of its size and its ability to form complexes as well as to stimulate transcription in vitro,” Latchman wrote. “The spectrum of transcription factors present determines what genes may be transcribed in a cell type, including genes that encode further transcription factors.”
However, newer techniques are helping researchers to reach conclusions much faster and much more reliably. Researchers have been taking advantage of protein microarrays to check their samples for the presence of transcription factors or stretches of DNA-binding sequences. You can also find several types of ELISA assays and antibodies that are designed to identify transcription factors. Or, you can purchase systems that contain plasmids that carry reporter genes, such as luciferase or green fluorescent protein (GFP). Co-transfecting a plasmid containing a gene of interest will indicate the activation of transcription.
The products below may also help you with your exploration of transcription factors. And the wide variety of options just may instill you with divine inspiration.
