PgmNr D1443: Role of axial patterning genes in growth regulation during eye development.

Authors:
N. GOGIA 1 ; M. KANGO SINGH 1,2,3 ; A. SINGH 1,2,3


Institutes
1) Department of Biology, University of Dayton, 300 College Park Drive, Dayton, OH; 2) Premedical Program, University of Dayton,OH; 3) Center for Tissue Regeneration & Engineering (TREND), University of Dayton, 300 College Park Drive, Dayton, OH.


Keyword: eye disc

Abstract:

An important question in developmental biology is that how growth regulation and cell fate specification genes work together during organogenesis to form a three-dimensional organ. In any multicellular organism, organogenesis requires axial patterning to determine Antero-Posterior (AP), Dorso-Ventral (DV), Proximo-Distal (PD) axes. Any deviation in these axes during development leads to congenital birth defects. We use Drosophila melanogaster (a.k.a fruit fly), eye as our model. In Drosophila, Dorso-Ventral (DV) patterning marks first lineage restriction event where axial patterning genes, regulates the formation of dorsal, ventral compartments in the eye. We have identified defective proventriculus (dve-a Homeobox gene), an ortholog of SATB homeobox 1 (special AT-rich sequence binding protein 1), as a new member of DV patterning gene hierarchy. We have shown that dve acts downstream of pannier (pnr, GATA-1 transcription factor), and upstream of wingless (wg) in dorsal gene hierarchy. Loss-of-function of dve or pnr results in dramatic dorsal eye enlargements, whereas gain-of-function suppresses the eye fate. We have demonstrated that Wg is a downstream target of Hippo growth regulatory pathway (highly conserved) in eye. Furthermore, Wingless (Wg), which acts downstream of dve, also exhibits similar eye enlargement and suppression phenotypes and has been shown to play a role in growth. Here, I present that DV patterning genes interact with Hippo signaling to regulate the common downstream target, Wg during growth and patterning of developing Drosophila eye. We are pursuing genetic epistatsis studies to determine how the members of these two highly conserved pathways regulate Wg signaling in the developing eye. Our data (using Gain-of-function studies) states that activation of Hippo signaling in dve, pnr expression domain results in change of fate. We have tested retinal determination fate markers in these backgrounds. This study will address an important question-if the axial patterning genes (dve, pnr) and Hippo pathway regulates patterning, growth independently or in-coordination with each other by regulating Wg signaling to form an eye/or any organ. Our study will have significant bearing on developmental mechanisms during organogenesis of the eye.



Flybase Genetic Index:
1. FlyBase gene symbol: dve; FBgn: FBgn0020307
2. FlyBase gene symbol: pnr; FBgn: FBgn0003117