ANALYSIS OF PERIOD CIRCADIAN EXPRESSION IN THE DROSOPHILA HEAD BY IN-SITU HYBRIDIZATION

The expression of the period (ppi) gene of Drosophila melanogaster has been studied by in situ hybridization in the adult's head, where it i s required for the fly to exhibit behavioral circadian rhythms. We hav e used non-radioactive in situ hybridization to obtain a high sensitiv ity and specificity on head sections, with single cell resolution. Con sistent with previous per protein-or per reporter gene-expression, per -expressing cells were detected in the optic lobes and the central bra in, as well as in the head sensory organs: eyes, ocelli, maxillary pal ps and proboscis. In the brain and the eyes, circadian fluctuations of the per mRNA abundance were observed in different per expressing cell s.