Meeting Abstract
Species occurring in aquatic habitats are subjected to a range of optical stimuli. Previous investigations have shown that Nematostella vectensis, a coastal cnidarian, responds to diel lighting patterns with an endogenous circadian clock, however, the impact of variable light remains unknown. In order to investigate how variation in optical stimuli impacts this anemone, we characterized differentially expressed genes and associated behaviors in N. vectensis as individuals responded to variable lighting conditions (duration and wavelength). Using microarrays we measured transcriptome-wide oscillations in gene expression to determine which genes cycle in light:dark (LD) conditions and which of these continue cycling after removal of the light cue (dark:dark, DD). Comparisons of LD and DD exposed animals revealed approximately 220 genes with significant differences in expression in light:dark culturing, with more than 85% of these losing differential expression within 4-days after removal of light cue. Using quantitative PCR we further investigated subsets of these genes in order to elucidate the impact of light cycling on optically related molecular pathways, some of which are regulated by a circadian clock – i.e. cell cycle/cell death, metabolism, and expression of light-sensitive proteins (opsins). We also used anemone locomotion analyses to determine if isolated portions of the visible spectrum elicited an alternative behavioral response, with preliminary results indicating they respond to all light wavelengths. Overall, these analyses provide insight into how this invertebrate responds to diel lighting conditions and wavelength, while shedding light onto the mechanism of cnidarian circadian clocks.
