Drosophila peripodial cells, more than meets the eye?

Abstract

Drosophila imaginal discs (appendage primordia) have proved invaluable for deciphering cellular and molecular mechanisms of animal development. By combining the accessibility of the discs with the genetic tractability of the fruit fly, researchers have discovered key mechanisms of growth control, pattern formation and long-range signaling. One of the principal experimental attractions of discs is their anatomical simplicity - they have long been considered to be cellular monolayers. During larval stages, however, the growing discs are 2-sided sacs composed of a columnar epithelium on one side and a squamous 'peripodial' epithelium on the other. Recent studies suggest important roles for peripodial epithelia in processes previously assumed to be confined to columnar cell monolayers.

Control of cell flattening and junctional remodeling during squamous epithelial morphogenesis inDrosophila

“…These are often associated with developmental or tissue remodeling processes. Examples include the trophectoderm of the mammalian embryo (Yamanaka et al, 2006) and the peripodial epithelium of Drosophila imaginal disks (Gibson and Schubiger, 2001). Cells also flatten and spread during epiboly (Solnica-Krezel, 2006) and wound healing (Van Aelst and Symons, 2002).…”

Apical and lateral cell protrusions interconnect epithelial cells in live Drosophila wing imaginal discs

“…1A; reviewed in Cohen, 1993). Signaling among columnar cells as well as between columnar and squamous cells is important for growth and patterning of wing imaginal discs (reviewed in Ramirez-Weber and Kornberg, 2000; Gibson and Schubiger, 2001). Several protrusions have been identified in imaginal discs.…”

how functions in leg development during Drosophila metamorphosis

“…Pastor-Pareja et al (2004) have proposed an interesting alternative to the long-held hypothesis that during imaginal disc eversion, contraction of the peripodial epithelium is the sole mechanism driving the movement of the appendage to the outside of the larval epidermis (Fristrom and Fristrom, 1993;Gibson and Schubiger, 2001). Pastor-Pareja et al (2004) propose an updated model for imaginal disc eversion, which invokes additional cellular events.…”

“…Drosophila leg development involves changes in cell shape, interactions between cells, and inflation of structures by hydrostatic pressure (Bayer et al, 2003;Fortier et al, 2003;Chen et al, 2004). The legs and a number of other Drosophila adult structures originate from imaginal discs, which are epithelial sacs with two apposing surfaces, a columnar imaginal epithelium and a squamous peripodial epithelium (Gibson and Schubiger, 2001). The primordia of the thoracic imaginal discs originate during embryogenesis as groups of cells spanning the parasegment boundary.…”

“…During imaginal disc eversion, the peripodial epithelium is involved in the movement of the appendage to the outside of the larval epidermis (Fristrom and Fristrom, 1993;Gibson and Schubiger, 2001). Pastor-Pareja et al (2004) have shown that, in a process requiring the JNK signaling pathway, imaginal disc eversion is driven by invasion of the larval epidermis by cells of the peripodial epithelium and stalk, followed by perforation of the peripodial stalk/larval bilayer, and protrusion of the imaginal epithelium.…”