Molecular Cloning of Genes Under Control of the Circadian Clock in Neurospora

Abstract

To investigate the regulation of messenger RNA abundance by circadian clocks, genomic and complementary DNA libraries were screened with complementary DNA probes enriched, by means of sequential rounds of subtractive hybridization, for sequences complementary to transcripts specific to either early morning or early evening cultures of Neurospora. Only two morning-specific genes were identified through this protocol. RNA blot analysis verified that the abundance of the transcripts arising from these genes oscillates with a period of 21.5 hours in a clock wild-type strain and 29 hours in the long-period clock mutant strain frq7. Genetic mapping through the use of restriction fragment length polymorphisms shows the two genes, ccg-1 and ccg-2, to be unlinked. These data provide a view of the extent of clock control of gene expression.

Circadian rhythmicity mediated by temporal regulation of the activity of p38 MAPK

“…Together, these data indicated that rrg-1 is the locus mutated in the COP1-4 strain. In wild-type strains, ccg-1 mRNA accumulates with a circadian rhythm, with peak levels occurring Ϸ12 h after entering DD (DD12) and a trough in ccg-1 mRNA levels occurring around DD24 (10). In the COP1-4 strain, ccg-1 mRNA levels are arrhythmic and constitutively low (19).…”

“…10). To date, Ͼ180 ccgs have been identified in N. crassa (10)(11)(12)(13)(14), including genes associated with rhythms in asexual spore development (conidiation; ref. 15), metabolism (16), pheromone production (17), and stress responses (18).…”

Polarized Gene Expression Determines Woronin Body Formation at the Leading Edge of the Fungal Colony

“…We examined the ccg-1 gene (clock controlled gene; Loros et al, 1989, also known as grg-1, glucose regulated gene; McNally and Free, 1988), which encodes an abundant transcript (McNally and Free, 1988) that is subject to complex physiological regulation (McNally and Free, 1988;Loros et al, 1989;Arpaia et al, 1995;Kimpel and Osiewacz, 1999). In our system, ccg-1 is enriched 200-fold in basal regions of the colony, whereas other transcripts are expressed throughout the colony (Figure 2C).…”

Profile of Jay C. Dunlap

“…Meanwhile, Loros, working at Dartmouth as a postdoctoral fellow, began the first screens for clock-controlled genes or ccgs, which have products that are involved in circadian output rather than the core circadian mechanism. The frq gene was cloned in 1986, and the first ccgs were found in 1987, with both results published in 1989 (4,5). The cloning of frq was featured on the cover of Nature, the first of seven journal covers featuring the work by Dunlap and Loros.…”