CUT INTERACTS WITH NOTCH AND PROTEIN-KINASE-A TO REGULATE EGG CHAMBERFORMATION AND TO MAINTAIN GERMLINE CYST INTEGRITY DURING DROSOPHILA OOGENESIS

Communications between the germline and the soma during Drosophila oog enesis have been previously shown to be essential for the formation of egg chambers and to establish polarity in the developing oocyte, In t his report, we demonstrate that the function of a somatically expresse d gene, cut, is critical for maintaining the structural integrity of g ermline-derived cells and their arrangement within an egg chamber, Gen etic manipulations of cut activity resulted in defective packaging of germline-derived cysts into egg chambers and disintegration of the str uctural organization of oocyte-nurse cell complexes to generate multin ucleate germline-derived cells, We also found that cut interacts genet ically with the Notch gene and with the catalytic subunit of Protein k inase A gene during egg chamber morphogenesis. Since cut expression is restricted to the somatic follicle cells and cut mutant germline clon es are phenotypically normal, we propose that the defects in the assem bly of egg chambers and the changes in germline cell morphology observ ed in cut mutant egg chambers are the result of altered interactions b etween follicle cells and germline cells, cut encodes a nuclear protei n containing DNA-binding motifs, and we suggest that it participates i n intercellular communications by regulating the expression of molecul es that directly participate in this process.