WC-2 is a GATA transcription factor necessary for blue light photoreception and for regulating circadian rhythms in Neurospora.
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.
[8] WC-2 has a GATA-family Zinc finger (ZnF) DNA-binding motif that allows the WCC to bind to promoter elements of light-induced genes such as frq.
Light-driven expression of frq relies on light as an input, occurs during daytime, and is mediated by the PLRE.
Clock-driven expression occurs in dark conditions during the night and is mediated by a separate region of the frq promoter, the Clock Box.
This was determined via experiments reducing or extinguishing CK1 and/or CK2 activity which showed increased levels of WCC binding to the frq promoter.
[4] WC-1 and WC-2 are thought to be the only non-redundant and non-essential genes that are involved in the positive regulation of light-induced mechanisms in Neurospora crassa.
[13] WC-1 and WC-2 are bound together to form the White Collar Complex (WCC) in cultures maintained in both light or dark.
It is then assumed that general transcription factors will initiate gene expression although the exact mechanism for this interaction is presently unknown.
[4] The general mechanism of interaction between WC-1 and WC-2 has been determined by looking at similar genes with LOV domains, such as VVD (Vivid) another blue light sensor used for photoadaptation.
Vivid responds to changes in light intensity and can silence the expression of WC related genes.