# MOLECULAR ANALYSIS OF SEGMENTATION IN DROSOPHILA

> **NIH NIH R01** · PRINCETON UNIVERSITY · 1994 · $248,764

## Abstract

The goal of this work is to understand how complex patterns of
differentiation are established in epithelial cells during Drosophila
development.  Much of the focus is on the middle period of embryogenesis,
from germ band extension to the onset of cell differentiation.  During
these stages, the segmental pattern established at the blastoderm stage has
its first consequences on cell behavior.  The maintenance of segmental
pattern during these stages depends on cell communication mediated by the
segment polarity genes.  Homeotic identity of the individual segments must
also be established during these stages so that cells can show their
segment specific morphologies at differentiation.

A substantial fraction of our work will focus on the segment polarity gene
armadillo (=arm).  arm is the homolog of plakoglobin, a vertebrate protein
found in a variety of adhesive junctions.  AT mid-embryonic stages arm
protein staining accumulates in regions of the epidermis that express
another segment polarity gene, wingless.  We will investigate the cellular
mechanisms responsible for this accumulation, and determine whether it
represent increased levels, modifications, or changes in intracellular
distribution.  We will use heat shock constructs to manipulate the level of
arm protein, and determine the consequences on the final embryonic
phenotype.  We will investigate the requirement for arm in those embryonic
cells that do not show high arm staining and will extend our studies of the
arm/wg signalling pathway to development of the larval epidermis and the
imaginal discs.

We will analyze the earliest cellular responses of the embryo to blastoderm
pair-rule expression, using cell intercalation during germband extension.
We will identify the pair-rule genes that affect germ band extension and
use a variety of morphological techniques to characterize the effects of
cell behavior in embryos mutant for those genes.  To identify the
downstream genes that mediate the cellular responses, we will examine the
phenotype of homozygous deletion embryos and analyze enhancer trap lines
which express betagal in pair-rule pattern during germ band extension.

We will complete the cloning of extradenticle (=exd) which have shown to be
necessary for the normal morphological consequences of homeotic gene
expression.  We will determine the expression pattern of exd in the embryo
and in imaginal discs.  We will begin a molecular analysis of the
interactions of that gene with Ubx protein.  We will also investigate the
role of exd in patterning in the imaginal discs.

## Key facts

- **NIH application ID:** 2198659
- **Project number:** 5R01HD022780-08
- **Recipient organization:** PRINCETON UNIVERSITY
- **SAM.gov UEI:** NJ1YPQXQG7U5
- **Principal Investigator:** ERIC F. WIESCHAUS
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 1994
- **Award amount:** $248,764
- **Award type:** 5
- **Project period:** 1987-04-01 → 1996-03-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/2198659

## Citation

> US National Institutes of Health, RePORTER application 2198659, MOLECULAR ANALYSIS OF SEGMENTATION IN DROSOPHILA (5R01HD022780-08). Retrieved via MORVS 2026-10-25 from https://api.morvs.ai/grant/nih/2198659. Licensed CC0.

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