Abstract
Miranda, a highly coiled-coil protein, has been shown to be one of the key components necessary for the differential segregation of fate-determining factors during neurogenesis in Drosophila embryos. The multidomain protein Miranda, by segregating the transcription factor Prospero, guarantees the generation of cell diversity during the formation of the embryonic nervous system. While looking for new molecular components of the centrosome in Drosophila embryos, we have isolated a short isoform of Miranda. An antibody was raised directed against the central coiled-coil region of Miranda. and the pattern of expression of the protein was studied in details throughout Drosophila development. Here, we show that Miranda has a broad pattern of expression and is a rather ubiquitous molecule. Immunofluorescence on syncytial Drosophila embryos shows that Miranda has a dynamic redistribution and is associated with centrosomes. Electron microscopy on purified syncytial centrosomes shows that Miranda is located on the pericentriolar material along with gamma-tubulin. Taken all together, our data indicate for the first time that Miranda belongs to a growing class of proteins that concentrate at the centrosome in a cell-cycle and stage-specific manner. The observations that Miranda has a broad range of expression, as well as a dynamic and cell-cycle dependent subcellular localization, suggest that it may have alternative functions outside the embryonic nervous system. These potential new functions are discussed in this paper.
