The white collar--2 (wc-2) gene in Neurospora crassa encodes the protein White Collar-2 (WC-2). WC-2 is a GATA transcription factor necessary for blue light photoreception and for regulating circadian rhythms in Neurospora. In both contexts, WC-2 binds to its non-redundant counterpart White Collar-1 (WC-1) through PAS domains to form the White Collar Complex (WCC), an active transcription factor.[1]
The WCC has two major and distinct roles in the cell. In the light, the WCC acts as a photoreceptor to mediate acute regulation of light-induced genes involved in various physiological processes such as carotenoid (type of pigment) biosynthesis and conidiation.[1] In a separate and distinct role in the dark, WCC acts as the positive element in the autoregulatory transcription-translation negative feedback loop that controls circadian rhythmic behaviors in Neurospora. In this context, WCC regulates expression of the Frequency (FRQ) gene, a light-induced clock protein.[2][3]