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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- Aronin N., Sagar S. M., Sharp F. R., Schwartz W. J. Light regulates expression of a Fos-related protein in rat suprachiasmatic nuclei. Proc Natl Acad Sci U S A. 1990 Aug;87(15):5959–5962. doi: 10.1073/pnas.87.15.5959. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Baima S., Macino G., Morelli G. Photoregulation of the albino-3 gene in Neurospora crassa. J Photochem Photobiol B. 1991 Nov;11(2):107–115. doi: 10.1016/1011-1344(91)80253-e. [DOI] [PubMed] [Google Scholar]
- Bell-Pedersen D., Dunlap J. C., Loros J. J. The Neurospora circadian clock-controlled gene, ccg-2, is allelic to eas and encodes a fungal hydrophobin required for formation of the conidial rodlet layer. Genes Dev. 1992 Dec;6(12A):2382–2394. doi: 10.1101/gad.6.12a.2382. [DOI] [PubMed] [Google Scholar]
- Dunlap J. C. Genetic analysis of circadian clocks. Annu Rev Physiol. 1993;55:683–728. doi: 10.1146/annurev.ph.55.030193.003343. [DOI] [PubMed] [Google Scholar]
- Earnest D. J., Iadarola M., Yeh H. H., Olschowka J. A. Photic regulation of c-fos expression in neural components governing the entrainment of circadian rhythms. Exp Neurol. 1990 Sep;109(3):353–361. doi: 10.1016/s0014-4886(05)80027-5. [DOI] [PubMed] [Google Scholar]
- Feinberg A. P., Vogelstein B. A technique for radiolabeling DNA restriction endonuclease fragments to high specific activity. Anal Biochem. 1983 Jul 1;132(1):6–13. doi: 10.1016/0003-2697(83)90418-9. [DOI] [PubMed] [Google Scholar]
- Giuliano G., Hoffman N. E., Ko K., Scolnik P. A., Cashmore A. R. A light-entrained circadian clock controls transcription of several plant genes. EMBO J. 1988 Dec 1;7(12):3635–3642. doi: 10.1002/j.1460-2075.1988.tb03244.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Harding R. W., Melles S. Genetic Analysis of Phototropism of Neurospora crassa Perithecial Beaks Using White Collar and Albino Mutants. Plant Physiol. 1983 Aug;72(4):996–1000. doi: 10.1104/pp.72.4.996. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Kornhauser J. M., Nelson D. E., Mayo K. E., Takahashi J. S. Photic and circadian regulation of c-fos gene expression in the hamster suprachiasmatic nucleus. Neuron. 1990 Aug;5(2):127–134. doi: 10.1016/0896-6273(90)90303-w. [DOI] [PubMed] [Google Scholar]
- Kornhauser J. M., Nelson D. E., Mayo K. E., Takahashi J. S. Regulation of jun-B messenger RNA and AP-1 activity by light and a circadian clock. Science. 1992 Mar 20;255(5051):1581–1584. doi: 10.1126/science.1549784. [DOI] [PubMed] [Google Scholar]
- Loros J. J., Feldman J. F. Loss of temperature compensation of circadian period length in the frq-9 mutant of Neurospora crassa. J Biol Rhythms. 1986 Fall;1(3):187–198. doi: 10.1177/074873048600100302. [DOI] [PubMed] [Google Scholar]
- McClung C. R., Fox B. A., Dunlap J. C. The Neurospora clock gene frequency shares a sequence element with the Drosophila clock gene period. Nature. 1989 Jun 15;339(6225):558–562. doi: 10.1038/339558a0. [DOI] [PubMed] [Google Scholar]
- Millar A. J., Short S. R., Chua N. H., Kay S. A. A novel circadian phenotype based on firefly luciferase expression in transgenic plants. Plant Cell. 1992 Sep;4(9):1075–1087. doi: 10.1105/tpc.4.9.1075. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Perkins D. D., Radford A., Newmeyer D., Björkman M. Chromosomal loci of Neurospora crassa. Microbiol Rev. 1982 Dec;46(4):426–570. doi: 10.1128/mr.46.4.426-570.1982. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Rusak B., Robertson H. A., Wisden W., Hunt S. P. Light pulses that shift rhythms induce gene expression in the suprachiasmatic nucleus. Science. 1990 Jun 8;248(4960):1237–1240. doi: 10.1126/science.2112267. [DOI] [PubMed] [Google Scholar]
- Russo V. E. Blue light induces circadian rhythms in the bd mutant of Neurospora: double mutants bd,wc-1 and bd,wc-2 are blind. J Photochem Photobiol B. 1988 Jul;2(1):59–65. doi: 10.1016/1011-1344(88)85037-1. [DOI] [PubMed] [Google Scholar]
- Sargent M. L., Briggs W. R. The effects of light on a circadian rhythm of conidiation in neurospora. Plant Physiol. 1967 Nov;42(11):1504–1510. doi: 10.1104/pp.42.11.1504. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Sargent M. L., Briggs W. R., Woodward D. O. Circadian nature of a rhythm expressed by an invertaseless strain of Neurospora crassa. Plant Physiol. 1966 Oct;41(8):1343–1349. doi: 10.1104/pp.41.8.1343. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Schmidhauser T. J., Lauter F. R., Russo V. E., Yanofsky C. Cloning, sequence, and photoregulation of al-1, a carotenoid biosynthetic gene of Neurospora crassa. Mol Cell Biol. 1990 Oct;10(10):5064–5070. doi: 10.1128/mcb.10.10.5064. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Siegel R. W., Matsuyama S. S., Urey J. C. Induced macroconidia formation in Neurospora crassa. Experientia. 1968 Nov 15;24(11):1179–1181. doi: 10.1007/BF02147840. [DOI] [PubMed] [Google Scholar]
- Sommer T., Chambers J. A., Eberle J., Lauter F. R., Russo V. E. Fast light-regulated genes of Neurospora crassa. Nucleic Acids Res. 1989 Jul 25;17(14):5713–5723. doi: 10.1093/nar/17.14.5713. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Taylor W. C. Transcriptional regulation by a circadian rhythm. Plant Cell. 1989 Feb;1(2):259–264. doi: 10.1105/tpc.1.2.259. [DOI] [PMC free article] [PubMed] [Google Scholar]