The Drosophila Pax gene eye gone is required for embryonic salivary duct development

Abstract

What are the developmental mechanisms required for conversion of an undifferentiated, two-dimensional field of cells into a patterned, tubular organ? In this report, we describe the contribution of the Drosophila Pax gene eye gone to the development of the embryonic salivary glands and ducts. eye gone expression in salivary tissues is controlled by several known regulators of salivary fate. After the initial establishment of the salivary primordium by Sex combs reduced, fork head excludes eye gone expression from the pregland cells so that its salivary expression is restricted to the posterior preduct cells. trachealess, in contrast, activates eye gone expression in the posterior preduct cells. We have previously described the process by which fork head and the EGF receptor pathway define the border between the gland and duct primordia. Here we show that eye gone is required for the subdivision of the duct primordium itself into the posterior individual duct and the anterior common duct domains. In the absence of eye gone, individual ducts as well as the precursor of the adult salivary glands, the imaginal ring, are absent. We took advantage of this ductless phenotype to show that Drosophila larvae do not have an obligate requirement for salivary glands and ducts. In addition to its role in the salivary duct, eye gone is required in the embryo for the development of the eye-antennal imaginal disc and the chemosensory antennal organ.

Regulation of the retinal determination gene dachshund in the embryonic head and developing eye of Drosophila

“…Contrary to the perception that the expression and activity of members of the retinal determination network is limited to the developing eye, each member of the network is normally expressed within and regulates the development of several non-retinal tissues (Aldaz et al, 2003;Bonini et al, 1998;Cheyette et al, 1994;Czerny et al, 1999;Fabrizio et al, 2003;Jones et al, 1998;Kumar and Moses, 2001a;Leiserson et al, 1998;Martini et al, 2000a;Quiring et al, 1994;Seimiya and Gehring, 2000;Serikaku and O'Tousa, 1994). For example, the retinal determination gene dachshund regulates the development of the embryonic head, brain, optic lobes and central nervous system as well as the adult brain, mushroom bodies, antennae, legs and genitals (Keisman and Baker, 2001;Kurusu et al, 2000;Mardon et al, 1994;Martini et al, 2000b;Noveen et al, 2000b;Rauskolb, 2001).…”

Organogenetic transcriptomes of the Drosophila embryo at single cell resolution

“…Among these are the HOX TF that specifies the SG ( Sex combs reduced – Scr ) ( Andrew et al, 1994 ; Panzer et al, 1992 ) and the SP1-like TF required for spatially ordered internalization of the primordia ( hückebein – hkb ) ( Myat and Andrew, 2000b , 2002 ; Sánchez-Corrales et al, 2021 ). Also among the temporally regulated SG TFs are those initially expressed in the entire primordium (duct and secretory cells) that later become restricted to only duct [ twin of eyegone ( toe ), eyegone ( eyg ) and trachealess ( trh )] ( Isaac and Andrew, 1996 ; Jones et al, 1998 ). Other SG TF genes, especially those regulating SG physiology, are activated early and continue to be expressed in all SG cells through metamorphosis and in the adult SG [ Cyclic-AMP response element binding protein A ( CrebA ), fork head ( fkh ), sage and senseless ( sens )] ( Abrams and Andrew, 2005 ; Abrams et al, 2006 ; Chandrasekaran and Beckendorf, 2003 ; Fox et al, 2010 , 2013 ; Zhou et al, 2001 ).…”

Fine structure of Drosophila larval salivary gland ducts as revealed by laser confocal microscopy and SEM

“…In the course of our SEM studies on the surface properties and internal substructure of exocytosed and expectorated glue (Beňová-Liszeková et al, 2019b), we found that the internal lining of the tubular, non-secretory structure of the SG, i.e., the duct that develops during embryogenesis by the coordinated action of a differently expressed set of genes, in contrast to the SG proper (Kuo et al, 1996;Jones et al, 1998;Yao & Sun, 2005), shows peculiar structures resembling tracheal taenidia. Using classical light microscopy, the potential presence of taenidial-like chitinous circumferential rings in Drosophila SG duct was noticed by Robertson (1936) andRoss (1939).…”