Document Type


Publication Date


Publication Title

American Journal of Plant Physiology


Geisel School of Medicine


Ambient light is the major agent mediating entrainment of circadian rhythms and is also a major factor influencing development and morphogenesis. We show that in Neurospora crassa the expression of clock-controlled gene 2 (ccg-2), a gene under the control of the circadian clock and allelic to the developmental gene easy wettable (eas), is regulated by light in wild-type strains. Light elicits a direct and important physiological effect on ccg-2(eas) expression as demonstrated using several mutant Neurospora strains. In white collar mutants (wc-1 and wc-2) that are “blind” to blue light, ccg-2(eas) mRNA shows no variation following illumination with saturating light. By contrast, ccg-2(eas) mRNA is photoinduced in clock-null strains such as frequency9 (bd;frq9). The results in the clock mutants show that an intact circadian oscillator is not required for light induction of ccg-2(eas). Thus, ccg-2(eas) is subject to a dual regulation that involves separable regulation by light and circadian rhythm.



Original Citation

Arpaia G, Loros JJ, Dunlap JC, Morelli G, Macino G. The interplay of light and the circadian clock. Independent dual regulation of clock-controlled gene ccg-2(eas). Plant Physiol. 1993;102(4):1299-1305. doi:10.1104/pp.102.4.1299