Inverse correlation between mean nuclear DNA content and cell number in nurse cell clusters of Drosophila

In the Drosophila ovarian follicle, 15 polyploid nurse cells (NC) are linked by cytoplasmic bridges to the anterior pole of the oocyte. The mutant dicephalic occasionally produces aberrant follicles whose 15 nurses cells are separated into two clusters, each attached to one oocyte pole (split nurse cell (SNC) follicles). Feulgen cytophotometry of isolated nuclei from such clusters and from normal follicles of the same females revealed an inverse correlation between NC number per cluster and mean DNA content per nucleus. The findings indicate that replication in NC nuclei is controlled with reference to the transcriptional capacity of the individual NC cluster rather than the total capacity available per oocyte or follicle.