Cryptochrome in Sponges

Abstract

SummarySponges (phylum: Porifera) react to external light or mechanical signals with contractile or metabolic reactions and are devoid of any nervous or muscular system. Furthermore, elements of a photoreception/phototransduction system exist in those animals. Recently, a cryptochrome-based photoreceptor system has been discovered in the demosponge. The assumption that in sponges the siliceous skeleton acts as a substitution for the lack of a nervous system and allows light signals to be transmitted through its glass fiber network is supported by the findings that the first spicules are efficient light waveguides and the second sponges have the enzymatic machinery for the generation of light. Now, we have identified/ cloned in Suberites domuncula two additional potential molecules of the sponge cryptochrome photoreception system, the guanine nucleotide-binding protein β subunit, related to β-transducin, and the nitric oxide synthase (NOS)-interacting protein. Cryptochrome and NOSIP are light-inducible genes. The studies show that the NOS inhibitor L-NMMA impairs both morphogenesis and motility of the cells. Finally, we report that the function of primmorphs to produce reactive nitrogen species can be abolished by a NOS inhibitor. We propose that the sponge cryptochrome-based photoreception system, through which photon signals are converted into radicals, is coupled to the NOS apparatus. ( J Histochem Cytochem 61:814-832, 2013)

The Gain and Loss of Cryptochrome/Photolyase Family Members during Evolution

“…Some of them are only characterized by the presence of sporadic α-helices of the 6-4 photolyase (α8, α10, sl & α18, see also Supplementary Materials S5 ). Studies on the sponge Suberites domuncula indicate that these CRYs are photosensitive and involved in various processes such as phototactic behavior, phototransduction, and circadian rhythmicity [ 76 , 77 ]. This suggests that the common ancestor of the Porifera and Bilateria already possessed an animal CRY.…”

“…However, at least in cnidarians lacking both TIM and PER, also clocks consisting only of MCRY or MCRY-ACRY are conceivable [ 80 ]. Even in the more primitive sponges appearing also to lack PER and TIM, species-specific CRYs continue to play a role in the circadian clock [ 76 , 77 ]. CRYs appear to be more primordially involved in the circadian clock than their common associates PERIOD, TIMELESS, CLOCK, and CYCLE.…”