The advent of fluorescent protein labeling technology has revolutionized cell biology by providing the means to study precise localization and dynamics of proteins within living cells. As this technology has evolved, there have been great advances both in the number of spectrally distinct fluorescent labels available and in the microscopes used to detect them. In fact, elegant studies that include distinct fluorescent entities used together in single cells now have become commonplace in the literature. However, the conventional fluorescent reporting technologies themselves exhibit one fundamental drawback to the scientist: each of the fluorescently labeled proteins requires individual cloning of the gene of interest fused to the fluorescent tag sequence. In other words, researchers must make a separate construct for each “color” of fluorescent tag they wish to put on a protein of interest. The HaloTag® labeling technology eliminates this time-consuming issue for biologists.
Promega Notes 101, 5–7.