A Mathematical Model of Communication between Groups of Circadian Neurons in Drosophila melanogaster

RISAU GUSMAN, SEBASTIAN; GLEISER, PABLO M.

JOURNAL OF BIOLOGICAL RHYTHMS.

SAGE PUBLICATIONS INC

Lugar: Thousand Oaks, California.; Año: 2014 vol. 29 p. 401 - 410

0748-7304

n the fruit fly, circadian behavior is controlled by a small number ofspecialized neurons, whose molecular clocks are relatively well known.However, much less is known about how these neurons communicate amongthemselves. In particular, only 1 circadian neuropeptide, pigment-dispersingfactor (PDF), has been identified, and most aspects of its interaction with themolecular clock remain to be elucidated. Furthermore, it is speculated thatmany other peptides should contribute to circadian communication. We havedeveloped a relatively detailed model of the 2 main groups of circadian pace-maker neurons (sLNvs and LNds) to investigate these issues. We have pro-posed many possible mechanisms for the interaction between thesynchronization factors and the molecular clock, and we have comparedthe outputs with the experimental results reported in the literature both for thewild-type and PDF-null mutant. We have studied how different the propertiesof each neuron should be to account for the observations reported for thesLNvs in the mutant. We have found that only a few mechanisms, mostlyrelated to the slowing down of nuclear entry of a circadian protein, can syn-chronize neurons that present these differences. Detailed immunofluorescentrecordings have suggested that, whereas in the mutant, LNd neurons are syn-chronized, in the wild-type, a subset of the LNds oscillate faster than the rest.With our model, we find that a more likely explanation for the same observa-tions is that this subset is being driven outside its synchronization range anddisplays therefore a complex pattern of oscillation.