Asymmetric requirement of Dpp/BMP morphogen dispersal in the Drosophila wing disc

Abstract

SummaryMorphogen gradients provide positional information and control growth in developing tissues, but the underlying mechanisms remain largely unknown due to lack of tools manipulating morphogen gradients. Here, we generate two synthetic protein binder tools manipulating different parameters of Decapentaplegic (Dpp), a morphogen thought to control Drosophila wing disc patterning and growth by dispersal; while HA trap blocks Dpp dispersal, Dpp trap blocks Dpp dispersal and signaling in the source cells. Using these tools, we found that while posterior patterning and growth require Dpp dispersal, anterior patterning and growth largely proceed without Dpp dispersal. We show that dpp transcriptional refinement from an initially uniform to a localized expression and persistent signaling in transient dpp source cells render the anterior compartment robust to blocking Dpp dispersal. Furthermore, neither Dpp dispersal nor signaling is critical for lateral wing growth. These results challenge Dpp dispersal-centric mechanisms, and demonstrate the utility of customized protein binder tools to dissect protein functions.

Heterodimerization-dependent secretion of BMPs in Drosophila

“…To visualize endogenous ligands in situ , we used CRISPR/Cas9 editing to introduce small epitope tags into the open reading frame of the endogenous gbb locus. Previous attempts tagging BMPs with bulky fluorescent proteins has been shown to result in partial loss of function (Matsuda et al, 2021; Akiyama, Wharton, personal commun.). Hence, we knocked in the short tags HA and OLLAS using ssDonor templates (Fig 1A and material and methods).…”

“…These tools permit the acute manipulation of tagged proteins in predictable manners, thus opening the door for experiments that were, thus far, out of reach. With respect to the BMP pathway, the combination of endogenous tagging and protein binders has permitted the interrogation of Dpp dispersal (Harmansa, Hamaratoglu, Affolter, & Caussinus, 2015; Matsuda et al, 2021), the construction of a minimal synthetic morphogen (Stapornwongkul, de Gennes, Cocconi, Salbreux, & Vincent, 2020) and here, the detection of heterodimers. It is by combining these and other emerging tools with the power of genetics that we will better understand how proteins coordinate development.…”

Acute manipulation and real-time visualization of membrane trafficking and exocytosis inDrosophila

“…Manipulating proteins rather than gene expression is required in situations where perdurance of proteins due to slow turnover upon genetic knockout or RNAi-mediated knock-down precludes loss-of-function phenotypes. While nanobody-based approaches allow to interfere with proteins by re-localizing (Harmansa et al, 2017), trapping (Matsuda et al, 2021) or degrading them (Caussinus et al, 2012), reversible retention by streptavidin hooks offers the additional potential to acutely restore protein localization and function upon addition of biotin. This will enable powerful functional experiments with precise temporal control, for instance allowing to release a signaling molecule from a defined source at a defined time and to determine the spatiotemporal dynamics of dispersal of the signaling molecule in the tissue and its effects across a field of cells.…”

Protein manipulation using single copies of short peptide tags in cultured cells and in Drosophila melanogaster

“…gelsolin and CapG ( Van Audenhove et al, 2013 ). Moreover, a very recent report showed the efficient trapping of an extracellular POI (Dpp), endogenously tagged with a single HA copy, using a functionalized anti-HA_scFv ( Matsuda et al, 2020 preprint).…”

“…Mislocalization or trapping of some POIs, tagged with FP, has been developed with anti-GFP nanobodies (Harmansa et al, 2017;Seller et al, 2019), anti-mTFP DARPin (Vigano et al, 2018), anti-mCherry nanobody (Prole and Taylor, 2019) but also with nanobodies against endogenous, non-tagged proteins, for example Gelsolin and CapG (Van Audenhove et al, 2013). Moreover, a very recent report showed the efficient trapping of an extracellular POI (Dpp), endogenously tagged with a single HA copy, using a functionalized anti-HA_scFv (Matsuda et al, 2020).…”