Open AccessA Circadian Oscillator in Aspergillus spp . Regulates Daily Development and Gene Expression
Author(s) -
Andrew V. Greene,
Nancy P. Keller,
Hubertus Haas,
Deborah Bell-Pedersen
Publication year - 2003
Publication title -
eukaryotic cell
Language(s) - English
Resource type - Journals
eISSN - 1535-9778
pISSN - 1535-9786
DOI - 10.1128/ec.2.2.231-237.2003
Subject(s) - neurospora crassa , circadian rhythm , biology , aspergillus nidulans , circadian clock , period (music) , oscillating gene , microbiology and biotechnology , bacterial circadian rhythms , clock , gene , glyceraldehyde 3 phosphate dehydrogenase , gene expression , crassa , rhythm , endogeny , genetics , medicine , biochemistry , endocrinology , mutant , physics , acoustics
We have established the presence of a circadian clock in Aspergillus flavus and Aspergillus nidulans by morphological and molecular assays, respectively. In A. flavus, the clock regulates an easily assayable rhythm in the development of sclerotia, which are large survival structures produced by many fungi. This developmental rhythm exhibits all of the principal clock properties. The rhythm is maintained in constant environmental conditions with a period of 33 h at 30 degrees C, it can be entrained by environmental signals, and it is temperature compensated. This endogenous 33-h period is one of the longest natural circadian rhythms reported for any organism, and this likely contributes to some unique responses of the clock to environmental signals. In A. nidulans, no obvious rhythms in development are apparent. However, a free running and entrainable rhythm in the accumulation of gpdA mRNA (encoding glyceraldehyde-3-phosphate dehydrogenase) is observed, suggesting the presence of a circadian clock in this species. We are unable to identify an Aspergillus ortholog of frequency, a gene required for normal circadian rhythmicity in Neurospora crassa. Together, our data indicate the existence of an Aspergillus circadian clock, which has properties that differ from that of the well-described clock of N. crassa.