Temporal and spatial expression patterns of transgenes containing increasing amounts of the Drosophila clock gene period and a lacZ reporter: mapping elements of the PER protein involved in circadian cycling.

Rhythmic oscillations of the PER protein, the product of the Drosophila period (per) gene, in brain neurons of the adult fly are strongly involved in the control of circadian rhythms. We analyzed temporal and spatial expression patterns of three per-reporter fusion genes, which share the same 4 kb regulatory upstream region but contain increasing amounts of per's coding region fused in frame to the bacterial lacZ gene. The fusion proteins contained either the N-terminal half (SG), the N-terminal-two-thirds (BG), or nearly all (XLG) of the PER protein.

Dosage compensation of the period gene in Drosophila melanogaster.

The period (per) gene is located on the X chromosome of Drosophila melanogaster. Its expression influences biological clocks in this fruit fly, including the one that subserves circadian rhythms of locomotor activity. Like most X-linked genes in Drosophila, per is under the regulatory control of gene dosage compensation.

A promoterless period gene mediates behavioral rhythmicity and cyclical per expression in a restricted subset of the Drosophila nervous system.

Transgenic flies carrying a 7.2 kb piece of DNA from the period (per) gene were analyzed for the presence of circadian locomotor activity rhythms and fluctuations of per-encoded mRNA and protein. The 5' end of this genomic fragment is within the first intron, which precedes the coding region.

An ultrashort clock mutation at the period locus of Drosophila melanogaster that reveals some new features of the fly's circadian system.

A rhythm mutant of Drosophila melanogaster was induced by chemical mutagenesis and isolated by testing for locomotor activity rhythms, which in the new variant had periods of approximately 16 hr. The sex-linked mutation responsible for this ultrashort period causes 20-hr rhythms when heterozygous with a normal X. This semidominance notwithstanding, the new mutation was revealed to be an allele of the period (per) gene by noncomplementation with per-null variants, in the sense that females heterozygous for perT (as the ultrafast-clock allele is called) and per- exhibited periods that were much shorter than in the case of perT/+.

Behavior in light-dark cycles of Drosophila mutants that are arrhythmic, blind, or both.

Certain of the rhythm mutations in Drosophila melanogaster lead to arrhythmic locomotor activity (and aperiodic eclosion) in constant conditions. In light-dark (LD) cycles, however, such mutants exhibit clear fluctuations between high levels of activity when the lights are on and much lower ones when they are off. Our data, in contrast to some previous conclusions, strongly suggest that period0 (per0) adults are, in LD conditions, merely being "forced" into exhibiting periodic behavior.