Microarray analysis of natural socially regulated plasticity in circadian rhythms of honey bees.
Honey bee workers care for ("nurse") the brood around the clock without circadian rhythmicity, but then they forage outside with strong circadian rhythms and a consolidated nightly rest. This chronobiological plasticity is associated with variation in the expression of the canonical "clock genes" that regulate the circadian clock: nurse bees show no brain rhythms of expression, while foragers do. These results suggest that the circadian system is organized differently in nurses and foragers. Nurses switch to activity with circadian rhythms shortly after being removed from the hive, suggesting that at least some clock cells in their brain continue to measure time while in the hive. We performed a microarray genome-wide survey to determine general patterns of brain gene expression in nurses and foragers sampled around the clock. We found 160 and 541 transcripts that exhibited significant sinusoidal oscillations in nurses and foragers, respectively, with peaks of expression distributed throughout the day in both task groups. Consistent with earlier studies, transcripts of genes involved in circadian rhythms, including Clockwork Orange that has not been studied before in bees, oscillated in foragers but not in nurses. The oscillating transcripts also were enriched for genes involved in the visual system, "development" and "response to stimuli" (foragers), "muscle contraction" and "microfilament motor gene expression" (nurses), and "generation of precursor metabolites" and "energy" (both). Transcripts of genes encoding P450 enzymes oscillated in both nurses and foragers but with a different phase. This study identified new putative clock-controlled genes in the honey bee and suggests that some brain functions show circadian rhythmicity even in nurse bees that are active around the clock.
Department of Animal Sciences, University of Illinois at Urbana-Champaign, IL, USA. rodrgzzs@illinois.edu
Sandra L
SL
Rodriguez-Zas
Bruce R
BR
Southey
Yair
Y
Shemesh
Elad B
EB
Rubin
Mira
M
Cohen
Gene E
GE
Robinson
Guy
G
Bloch
D000818:Animals; D001516:Bees / Q000235:genetics / Q000502:physiology*; D001921:Brain / Q000378:metabolism*; D057906:Circadian Clocks / Q000235:genetics*; D002940:Circadian Rhythm / Q000235:genetics* / Q000502:physiology; D003577:Cytochrome P-450 Enzyme System / Q000235:genetics; D055106:Genome-Wide Association Study; D009043:Motor Activity / Q000235:genetics* / Q000502:physiology; D009419:Nerve Tissue Proteins / Q000235:genetics*; D020411:Oligonucleotide Array Sequence Analysis; D010507:Periodicity; D012333:RNA, Messenger / Q000032:analysis; D017299:Rod Opsins / Q000235:genetics; D012919:Social Behavior
D009419:Nerve Tissue Proteins; D012333:RNA, Messenger; D017299:Rod Opsins; D003577:Cytochrome P-450 Enzyme System