Regulatory circuits that enable proliferation of the fungus Candida albicans in a mammalian host

The ability of C. albicans to colonize and proliferate in the GI tract has been studied in mice receiving antibiotics orally; while these animals are not natural hosts of C. albicans, they likely serve as reasonable proxies. Because transcription regulators are central elements within the gene network of any organism, the use of them as entry points to the dissection of this trait has proved an effective strategy. By contrast, many "textbook" genetic circuits--those that most scientists have grown used to--consist of simple, unidirectional relationships among their components, making their behavior more predictable. Because of the distinctly interwoven appearance of the C. albicans circuit, it is difficult to predict its behavior without extensive knowledge of the parameters (e.g., concentration of proteins, affinity constants, and the like).