Shaping up for action

Abstract

The Malpighian tubule is the main organ for excretion and osmoregulation in most insects. During a short period of embryonic development the tubules of Drosophila are shaped, undergo differentiation and become precisely positioned in the body cavity, so they become fully functional at the time of larval hatching a few hours later. In this review I explore three developmental events on the path to physiological maturation. First, I examine the molecular and cellular mechanisms that generate organ shape, focusing on the process of cell intercalation that drives tubule elongation, the roles of the cytoskeleton, the extracellular matrix and how intercalation is coordinated at the tissue level. Second, I look at the genetic networks that control the physiological differentiation of tubule cells and consider how distinctive physiological domains in the tubule are patterned. Finally, I explore how the organ is positioned within the body cavity and consider the relationship between organ position and function.

Novel roles for GATAe in growth, maintenance and proliferation of cell populations in the Drosophila renal tubule

“…This organ persists from embryonic development throughout metamorphosis. However, during metamorphosis they still undergo tissue remodeling, initially shrinking by half their length and then elongating before eclosion (Denholm, 2013;Wessing and Eichelberg, 1979). Several factors have been shown to modulate changes in MT structure and function during this period, like the tumor suppressors salvador and Scribbled, which have been implicated in the regulation of the RNSCs (Zeng et al, 2010).…”

“…The formation and development of an organ is a complex process involving several programmed events, including changes in cell shape and adhesion, proliferation and differentiation (Hatton-Ellis et al, 2007;Wan et al, 2000;Ainsworth et al, 2000). Understanding the genetic pathways involved is crucial, as defects in any of these aforementioned processes can lead to malformations and lethality (Jung et al, 2005;Denholm, 2013;Ainsworth et al, 2000). These events can be readily studied in Drosophila melanogaster Malpighian tubules (MTs), a powerful model system for investigating mechanisms of cell differentiation, proliferation and development, as well as a model of kidney disease (Millet-Boureima et al, 2018;Dow and Romero, 2010).…”

“…Development of the MTs occurs during embryogenesis and they are completely functional by the first instar larval stage. The development and physiology of the fly renal tubule have been extensively investigated and reviewed in previous publications (Beyenbach et al, 2010;Denholm, 2013;Skaer, 1996;Dow, 2012;Beaven and Denholm, 2018;Bunt et al, 2010). Each tubule is composed of different segments (ureter, main, initial and transitional segments) that are functionally and genetically distinct (Chintapalli et al, 2012), and has two main epithelial cell types: the principal cell (PC) and the stellate cell (SC) (Dow, 2012;Denholm et al, 2003).…”

Physiology, Development, and Disease Modeling in the Drosophila Excretory System

“…Unusually for a Drosophila tissue, and in contrast to the rest of the hindgut, the tubule of the newly hatched insect is maintained for life, without extensive remodeling through pupation. There are further reviews available on tubule development (Jung et al 2005;Beyenbach et al 2010;Denholm 2013).…”

Building from the Ground up

“…In Drosophila, the BM has been implicated in signaling during tubule morphogenesis as well. The Drosophila kidney ortholog, the Malpighian tubules, exhibits stereotyped outgrowth guided by a leading group of “kink cells” at the tissue's anterior (Denholm, 2013). Local expression of the BMP homolog Decapentaplegic (Dpp) in tissues along the tubule outgrowth route is necessary and sufficient to guide this morphogenesis (Bunt et al, 2010).…”