Data CitationsNaylor RW, Davidson AJ
Data CitationsNaylor RW, Davidson AJ. tubule epithelial cells are changed into an endocrine gland known as the Corpuscles of Stannius (CS). We find that this process requires Notch signalling and is associated with the cytoplasmic sequestration of the Hnf1b transcription factor, a master-regulator of renal tubule fate. A deficiency in the Irx3b transcription factor results in ectopic transdifferentiation of distal tubule cells to a CS identity but in a Notch-dependent fashion. Using live-cell AZD1390 imaging we show that CS cells undergo apical constriction and are then extruded from the tubule to form a distinct organ. This system provides a valuable new model to understand the molecular and morphological basis of transdifferentiation and will advance efforts to exploit this rare phenomenon therapeutically. embryos with the indirect transdifferentiation of rectal epithelial Y cells into cholinergic motor neurons (Jarriault et al., 2008) and the formation of MCM interneurons from AMso glial cells (Sammut et AZD1390 al., 2015). In vertebrates, direct transdifferentiation is largely limited to the adult setting where it is associated with response to injury. For example, AZD1390 ablation of pancreatic -cells induces the transdifferentiation of resident -cells to -cells in both mice and zebrafish (Thorel et al., 2010; Ye et al., 2015). Similarly, in the liver, chronic injury promotes the conversion of hepatocytes to biliary epithelial cells through the combined action of the Notch and Hippo signalling pathways (Yanger et al., 2013). Cases of indirect transdifferentiation in vertebrates include the well-known example of lens regeneration in amphibians following lentectomy (Stone, 1967), in which retinal pigmented epithelial cells initiate expression of pluripotency genes (Maki et al., 2009), dedifferentiate and then mature into lens cells (Snchez Alvarado and Tsonis, 2006). Indirect transdifferentiation is considered to occur in some cancers, via the epithelial-to-mesenchymal transition and dedifferentiation that often accompanies tumourigenesis (Shekhani et al., 2013; AZD1390 Maddodi and Setaluri, 2010; Maniotis et al., 1999; Fang et al., 2005). In summary, while transdifferentiation in vivo is possible under normal and pathogenic settings, it remains a rare and poorly understood phenomenon. The zebrafish offers a visually accessible vertebrate model with which to study cell fate changes in the context of organogenesis. The embryonic kidney (pronephros) is particularly well-suited for these studies because of its readily visualised location within the embryo AZD1390 and a high degree of understanding of how cell division, differentiation and morphogenesis are co-ordinated during organ formation (Drummond et al., 1998; Majumdar et al., 2000; Wingert and Davidson, 2011; Wingert et al., 2007; Wingert and Davidson, 2008; Naylor et al., 2013; Naylor et al., 2016b; Naylor et al., 2017). The zebrafish pronephros is usually analogous to the filtering units in the mammalian kidney (nephrons) and consists of a midline-fused blood filter (glomerulus), attached to bilateral renal tubules that extend to the cloaca (Drummond et al., 1998; Wingert et al., 2007; Wingert and Davidson, NEU 2008; Drummond and Davidson, 2010). The tubules are subdivided into functionally distinct segments consisting of the proximal convoluted tubule (PCT), the proximal straight tubule (PST), the distal early tubule (DE), and the distal late segment (DL; Physique 1 and [Wingert et al., 2007]). Each tubule segment expresses a specific set of genes that defines its functional differentiation. The PCT and PST are associated with bulk re-absorption of solutes from the filtrate and express a wide variety of solute transporters (Wingert et al., 2007; Blaine et al., 2015; Ullrich and Murer, 1982). On the other hand, the DL and DE sections express fewer transporters, recommending that they function even more to fine-tune the structure from the filtrate. For instance, functionality from the DE portion is conferred with the appearance of embryo (best sections) and embryos set at the levels proven and stained for embryo co-labelled with Phalloidin (F-actin, crimson) and DAPI (nuclear stain, blue) at the website from the extruding CS at 38 hpf. (C) Histogram displays the frequency from the four levels of CS extrusion at 24 hpf, 32 hpf, 40 hpf and 50 hpf. (D) Sections.