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. 1993 Aug;102(4):1299–1305. doi: 10.1104/pp.102.4.1299

The interplay of light and the circadian clock. Independent dual regulation of clock-controlled gene ccg-2(eas).

G Arpaia 1, J J Loros 1, J C Dunlap 1, G Morelli 1, G Macino 1
PMCID: PMC158919  PMID: 8278550

Abstract

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 frequency (bd;frq). 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.

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Selected References

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