Simple Expression Domains Are Regulated by Discrete CRMs During Drosophila Oogenesis

Abstract

Eggshell patterning has been extensively studied in Drosophila melanogaster. However, the cis-regulatory modules (CRMs), which control spatiotemporal expression of these patterns, are vastly unexplored. The FlyLight collection contains >7000 intergenic and intronic DNA fragments that, if containing CRMs, can drive the transcription factor GAL4. We cross-listed the 84 genes known to be expressed during D. melanogaster oogenesis with the ∼1200 listed genes of the FlyLight collection, and found 22 common genes that are represented by 281 FlyLight fly lines. Of these lines, 54 show expression patterns during oogenesis when crossed to an UAS-GFP reporter. Of the 54 lines, 16 recapitulate the full or partial pattern of the associated gene pattern. Interestingly, while the average DNA fragment size is ∼3 kb in length, the vast majority of fragments show one type of spatiotemporal pattern in oogenesis. Mapping the distribution of all 54 lines, we found a significant enrichment of CRMs in the first intron of the associated genes’ model. In addition, we demonstrate the use of different anteriorly active FlyLight lines as tools to disrupt eggshell patterning in a targeted manner. Our screen provides further evidence that complex gene patterns are assembled combinatorially by different CRMs controlling the expression of genes in simple domains.

In locusanalysis of patterning evolution in the BMPR2 Wishful thinking

“…At the same time, dpp expression is regulated by a combination of the EGFR and JAK/STAT pathways (Peri and Roth, 2000;Xi et al, 2003). This was recently confirmed by a CRM analysis screen using the FlyLight collection (Revaitis et al, 2017). The same screen found additional CRMs with different extents of anterior coverage, including an anterior portion of the stretched cells, all stretched cells, and stretched cells and centripetally migrating follicle cells.…”

“…Clonal analysis of Brinker was conducted using the Flp/FRT system (Theodosiou and Xu, 1998) utilizing: FRT 19A BRK M68 /FRT 19A ubiGFP; e22c-GAL4 UAS-flp. A UAS-BRK (a gift from J. Duffy, Worcester Polytechnic Institute, MA, USA) was expressed with the oogenesis dpp:GAL4 driver (Revaitis et al, 2017). The trap lacZ of Brinker was used to mark BRK expression (X47[PlacZ(ry+)]) (Campbell and Tomlinson, 1999).…”

“…However, dpp is not regulated by BMP signaling; rather, it is regulated by a combination of the EGFR and Janus kinase/signal transducer and activator of transcription (JAK/STAT) pathways (Peri and Roth, 2000;Xi et al, 2003). This was recently confirmed by cis-regulatory module (CRM) analysis screening using the FlyLight collection (Revaitis et al, 2017). The Dad CRM responded to ectopic BMP signaling, whereas the dpp CRM did not.…”

Quantitative analyses of EGFR localization and trafficking dynamics in the follicular epithelium

“…4A) (Eden et al, 2009;Bakker et al, 2017). To test the reliability of the of Rab5 and Rab7 antibodies, Rab5-GFP and Rab7-GFP were expressed in the posterior FCs using the GAL4 driver pnt 43H01 (Revaitis et al, 2017). The Rab5 and Rab7 proteins were detected in the endosomal compartments and diffusely in the cytosol.…”

Two Drosophilids exhibit distinct EGF pathway patterns in oogenesis

“…One likely explanation lies in alterations to cis-regulatory regions, which are well- known drivers of evolutionary change (Carroll 2008). To date, there are two characterized br enhancer regions that are required for DA formation in D. melanogaster (Cheung et al 2013; Revaitis et al 2017). Changes in these enhancers, or the presence of additional enhancers unresponsive to Pnt and Cic, could ensure robust levels of br .…”