A hormonal cue promotes timely follicle cell migration by modulating transcription profiles

Abstract

Cell migration is essential during animal development. In the Drosophila ovary, the steroid hormone ecdysone coordinates nutrient sensing, growth, and the timing of morphogenesis events including border cell migration. To identify downstream effectors of ecdysone signaling, we profiled gene expression in wild-type follicle cells compared to cells expressing a dominant negative Ecdysone receptor or its coactivator Taiman. Of approximately 400 genes that showed differences in expression, we validated 16 candidate genes for expression in border and centripetal cells, and demonstrated that seven responded to ectopic ecdysone activation by changing their transcriptional levels. We found a requirement for seven putative targets in effective cell migration, including two other nuclear hormone receptors, a calcyphosine-encoding gene, and a prolyl hydroxylase. Thus, we identified multiple new genetic regulators modulated at the level of transcription that allow cells to interpret information from the environment and coordinate cell migration in vivo.

Temporal Coordination of Collective Migration and Lumen Formation by Antagonism between Two Nuclear Receptors

“…Other downstream factors besides E75B may also mediate ecdysone/ EcR signaling because E75B can only partially rescue EcR's loss-of-function phenotype in border cells. Consistently, a recent study using microarray analysis also identified E75 as one of the target genes that are responsive to ecdysone signaling in the migratory border cells (Manning et al, 2017).…”

“…We found that E75B overexpression markedly rescued EcR RNAi's migration defects, whereas E75C displayed a much weaker rescue effect and E75A showing no significant rescue (Figure 1B). Moreover, we found that E75's transcription levels (as represented by a previously used reporter E75-lacZ (Manning et al, 2017)) within border cells at stages 9 and 10 were much higher than those at stage 8 (Figure 1C), consistent with ecdysone signaling being significantly increased beginning at stage 9. And mosaic border cell clusters containing a clone of EcR RNAi-expressing cells demonstrate that E75B protein levels are drastically decreased when EcR function is reduced (Figure 1D), indicating that EcR activity is required for E75B expression during stage 9.…”

The Evolutionary Conserved Transmembrane BAX Inhibitor Motif (TMBIM) Containing Protein Family Members 5 and 6 Are Essential for the Development and Survival of Drosophila melanogaster

“…To monitor mitochondrial calcium and ER calcium, brains of pdf > > 4mtGCaMP3, RFP and pdf > erGAP3 adult flies were dissected and prepared as described in Manning et al (2017) and imaged by Leica SP2 with laser intensity 20%,…”

The Evolutionary Conserved Transmembrane BAX Inhibitor Motif (TMBIM) Containing Protein Family is Essential for the Development and Survival of Drosophila Melanogaster

“…ER Ca 2+ levels were quantitated by targeting the genetically-encoded ER Ca 2+ sensor erGAP3 29 to Pdf neurons in TMBIM-specific RNAi lines ( Figure 8a). Pdf neurons are easily detected and fluorescence can be quantified by confocal microscopy 30,31 . As we observed changes in the circadian rhythm upon pdf-neuronal KD in dmTMBIM3-6 flies, we expected alterations in at least these four fly lines.…”

“…Locomotor events were recorded by an infrared beam placed in the middle of each tube every 30 min for 10 days. 15 flies per genotype.MicroscopyBrains of 2-day-old Pdf>>UAS-erGAP3,UAS-RNAi adult fly were dissected as described in31 and imaged by Leica SP2 with laser intensity 20%, Alex488, Gain 20%.Confocal images were quantified by NIH ImageJ. Mean fluorescence intensity of erGAP3 of the Pdf neuron cluster from each animal was plotted by GraphPad Prism.…”