Ecdysone-related changes at the nuclear and cytoplasmic level of Malpighian tubule cells in Drosophila

Abstract

Following a natural or experimentally produced rise in moulting hormone titre, Malpighian tubule cells of Drosophila hydei display a change in the chromosomal puffing pattern similar to that observed in salivary gland cells. Following this change in genome activity, changes in the structural organization of the cytoplasm were observed. In cells of the anterior portion of the main segment, the basal area of the cell occupied by infoldings of the cell membrane becomes reduced. Glycogen deposits are less frequent in late third instar larvae as well as in mid-third instar larvae injected with hormone as compared with untreated mid-third instar larvae. Following a rise in hormone titre, ureter cells displayed a reduction of the area occupied by infoldings of the cell membrane, a reduced length of the microvilli, less rough endoplasmatic reticulum (RER), and an increased quantity of glycogen deposits. The possible relationship between a common genome response in functionally different cells and the changes at the cytoplasmic level of these cells is discussed.