Khalil Mazouni's research while affiliated with Institut Pasteur and other places

... ppn (papilin) encodes a components of the extracellular matrix (ECM) (Campbell et al, 1987) that is, as is most embryonic ECM, expressed by hemocytes during their embryonic migration and its expression therefore did not colocalise with fkh mRNA (Fig. 2 F, F'). E(spl) gene expression dominates one cluster (Couturier et al, 2019;Schrons et al, 1992), and analysis of a GFP trap in E(spl)mg revealed protein expression across the epidermis but excluded from the salivary gland placode marked by fkh mRNA (Fig. 2 G, G'). ...

... Twist both activates Fog and T48 and delays mesoderm cell division until after invagination via expression of the cell cycle inhibitor, Tribbles (Grosshans and Wieschaus, 2000;Seher and Leptin, 2000). Snail promotes apical myosin II recruitment and cell shape change, in part, by repressing the Bearded family of genes (Perez-Mockus et al., 2017). Mist expression is regulated by Snail, and modulated by Twist and Dorsal, while Smog is maternally deposited into the embryo (Manning et al., 2013;Kerridge et al., 2016;Carmon et al., 2021). ...

... As in other mitotic systems 16,17 , Actin is recruited to the SOP cortex at metaphase onset (Extended Data Fig. 1d) during the mitotic rounding process [18][19][20] . In contrast, in late anaphase, the posterior Actin cortex is enriched by fourfold (Fig. 1f,g, Supplementary Video 1 and Extended Data Fig. 1d-h) and is 40% thicker compared with the anterior cortex (Extended Data Fig. 1i,j). ...

... In Xenopus gastrula embryos, after asymmetric cleavage furrowing completes and the midbody is established, new tri-cellular tight junctions are formed basal to and on either end of the MB [59]. In Drosophila sensory organ precursor cell divisions, the new apical junction forms prior to abscission near the midbody [60]. In Drosophila ovary follicular epithelium, when apical junction proteins were experimentally mislocalized on baso-lateral membrane, midbodies formed more basally and epithelial invaginations were observed [61]. ...

... The reason for this prominent shift from MPC to PAC fate is presently unknown, but it was speculated that onset of Lunatic fringe expression around E14.5 in the distal part of the epithelium 43 might play a role. On a larger perspective, beyond the Notch-Delta system, then cell fate choices are sometimes found to be dependent on cell-intrinsic feedback 5,[44][45][46][47] . However, within paradigms that are governed by Notch-Delta systems, our model suggests a dependence on the cell-intrinsic feedback and illustrates how it plays out in early pancreas differentiation. ...

... It should be noted that Delta-endocytosis-independent Notch activation has been reported in tissue culture cells where a Delta ligand has been immobilized to the stiff support of the culture dish [45]. It is also noteworthy that Neur has evolved another type of activity, independently of Delta-Notch, which is to promote epithelial loosening via degradation of the Crumbs-Stardust complex [46,47]. Perhaps events of epithelial to mesenchymal transition triggered by Neur have co-opted Delta expression to accompany this tissue remodeling with the emission of a Delta-Notch signal (e.g., Contreras et al. [48]). ...

... In our first example, we explore the optimal performance of lateral inhibition signaling (LIS). Biologically, LIS is realized by the Delta-Notch pathway (31), which plays a key role in a broad range of self-organized developmental systems (9,(32)(33)(34)(35). In a minimal model of this pathway, each cell i produces a chemical g i , which inhibits the production of the same chemical in neighboring cells (36). ...

... Notch signaling is a pivotal regulator of cell cycle progression and apoptosis that is triggered by binding of Jag or DLL ligands with NOTCH receptors [153,154]. Binding of ligand to its receptor leads to proteolytic cleavages of Notch receptor via metalloproteinase and gamma-secretase, which release and translocate intracellular domain of Notch (Notch-ICD) to the nucleus [155,156]. ICD interacts with CBF1/Su(H)/Lag-1 (CSL) and induces the transcription of several NOTCH target genes such as SLUG, SNAIL1, ZEB1, HEY, HES, and CCND1, while down regulation of CDH1 to promote EMT [155,157,158]. ...

... The pupal notum has been widely used as a model epithelium because it is amenable to live imaging: the animals are immobile, and after dissection from the pupal case, the notum epithelium is easily visualized through the transparent nascent adult cuticle (O'Connor et al., 2022). Our lab has used the notum as a model for epithelial wound healing ~13-15 h APF (Shannon et al., 2017;O'Connor et al., 2021;Stevens et al., 2023), and it has also been used as a model epithelium to analyze cell extrusion and apoptosis (Marinari et al., 2012;Moreno et al., 2018;Valon et al., 2021), mitosis (Besson et al., 2015;Pinheiro et al., 2017), and other epithelial cell behaviors (Guirao et al., 2015). Despite its popularity as a tissue for basic research in epithelial biology, it is unknown when the basement membrane assembles in this tissue. ...

... The most enriched motif matches an ACCGTTA sequence, called F7-BS. The F7-BS motif was defined by a machine learning approach combining statistical analysis to phylogenetic information 33 as the best predictor of functional Svb binding sites in vivo. 28 Although peak calling detected a markedly smaller number of regions for Svb-REP (1,325 with MACS q value = 10e À4 ), regions bound by Svb-REP extensively overlapped with regions bound by Svb-ACT ( Figures 1C and 1D). ...