During development, cell fates are established by signals that emanate from specialized """"""""organizer"""""""" regions. How these signals direct cells to differentiate migrate, and alter their shape during development is a fundamental yet poorly understood question. The analysis of Hedgehog (Hh) and Wingless (Wg) signaling in Drosophila embryonic epidermis is contributing novel insights into these fundamental developmental problems. Preliminary work identified three conserved genes drumstick (drm), lines, and bowl. Their gene products interact physically to mediate patterning by the epidermal organizer. In imaginal discs, these gene products control epithelial morphogenesis by signals distinct from Hh and Wg. ? Genetic and biochemical experiments suggest the following model to be tested in Aims 1 and 2: Lines targets Bowl for degradation via the ubiquitin-proteasome pathway; Drm inhibits Lines to shield Bowl from degradation; Drm accomplishes this function by localizing Lines to the cytoplasm.
Specific Aim 1 is designed to test how Lines decreases the abundance of Bowl. A combination of genetic, molecular, and pharmacological approaches in cell culture and in vivo will link the activity of Lines to proteasomal, or non-proteasomal pathways.
Specific Aim 2 is designed to test whether Drm localizes Lines to the cytoplasm to stabilize Bowl and whether Drm accomplishes this function by decreasing Lines-Bowl interaction. ? Molecular genetic experiments suggest that Lines blocks epithelial folding in imaginal discs, whereas Drm inhibits Lines, and thereby activates Bowl, to initiate epithelial folding.
Specific Aim 3 utilizes a combination of loss- and gain-of-function experiments in mosaic clones to test the model. The proposed experiments will help explain how primary organizing signals direct cells to differentiate and alter their shape during development. Insight from this work may apply to vertebrate development where parallel pathways operate. In addition, the proposed experiments will provide essential insights into the regulation of the ubiquitin-proteasome system (or another proteolytic system) in a developmental setting. Insight from this work may suggest new strategies for reversing diseases that arise from constitutive degradation of key regulatory proteins. ? ?

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
5R01GM068069-04
Application #
7233600
Study Section
Genetics Study Section (GEN)
Program Officer
Haynes, Susan R
Project Start
2004-07-01
Project End
2009-06-30
Budget Start
2007-07-01
Budget End
2008-06-30
Support Year
4
Fiscal Year
2007
Total Cost
$255,488
Indirect Cost
Name
Tufts University
Department
Anatomy/Cell Biology
Type
Schools of Medicine
DUNS #
039318308
City
Boston
State
MA
Country
United States
Zip Code
02111
Del Signore, Steven J; Cilla, Rodrigo; Hatini, Victor (2018) The WAVE Regulatory Complex and Branched F-Actin Counterbalance Contractile Force to Control Cell Shape and Packing in the Drosophila Eye. Dev Cell 44:471-483.e4
Coravos, Jonathan S; Martin, Adam C (2016) Apical Sarcomere-like Actomyosin Contracts Nonmuscle Drosophila Epithelial Cells. Dev Cell 39:346-358
de Madrid, Beatriz Hernandez; Greenberg, Lina; Hatini, Victor (2015) RhoGAP68F controls transport of adhesion proteins in Rab4 endosomes to modulate epithelial morphogenesis of Drosophila leg discs. Dev Biol 399:283-95
Cilla, Rodrigo; Mechery, Vinodh; Hernandez de Madrid, Beatriz et al. (2015) Segmentation and tracking of adherens junctions in 3D for the analysis of epithelial tissue morphogenesis. PLoS Comput Biol 11:e1004124
Hatini, Victor; Kula-Eversole, Ela; Nusinow, David et al. (2013) Essential roles for stat92E in expanding and patterning the proximodistal axis of the Drosophila wing imaginal disc. Dev Biol 378:38-50
Del Signore, Steven J; Hayashi, Teru; Hatini, Victor (2012) odd-skipped genes and lines organize the notum anterior-posterior axis using autonomous and non-autonomous mechanisms. Mech Dev 129:147-61
Greenberg, Lina; Hatini, Victor (2011) Systematic expression and loss-of-function analysis defines spatially restricted requirements for Drosophila RhoGEFs and RhoGAPs in leg morphogenesis. Mech Dev 128:5-17
Greenberg, Lina; Hatini, Victor (2009) Essential roles for lines in mediating leg and antennal proximodistal patterning and generating a stable Notch signaling interface at segment borders. Dev Biol 330:93-104
Nusinow, David; Greenberg, Lina; Hatini, Victor (2008) Reciprocal roles for bowl and lines in specifying the peripodial epithelium and the disc proper of the Drosophila wing primordium. Development 135:3031-41
Hatini, Victor; Green, Ryan B; Lengyel, Judith A et al. (2005) The Drumstick/Lines/Bowl regulatory pathway links antagonistic Hedgehog and Wingless signaling inputs to epidermal cell differentiation. Genes Dev 19:709-18