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Poster Full Abstracts - Pattern Formation
Poster board number is above title. The first author is the presenter
323
716B
Odd-skipped genes organize growth and patterning along the notum anterior-posterior axis.
Steven J. DelSignore, Victor Hatini. Cell, Molecular &
Developmental Biol, Tufts Univ Sackler School Biomedical Sciences, Boston, MA.
The Drosophila wing imaginal disc undergoes extensive growth and patterning to give rise both to the wing blade and the dorsal thoracic body wall, or
notum. The coordination of growth and patterning has been well studied in the wing, but remains poorly characterized in the notum. Because the body wall
lacks the proximo-distal organization of the wing appendage, it is of interest to characterize whether these tissues share similar growth and patterning
mechanisms. We previously found that the odd-skipped proteins Drm, Odd, Sob, and Bowl accumulate along the anterior margin of the notum, and are
required for notum formation or expansion (Nusinow, 2008). Here we utilized loss- and gain-of-function clonal analyses to test the hypothesis that odd-
skipped gene activity at the margin promotes the identity and expansion of the notum anterior-posterior (AP) axis. We found that ectopic expression of Drm
promoted Bowl accumulation both within and adjacent to clones. Additionally, it promoted the anterior notum patterning gene
eyegone
(
eyg
), both within
and many cell diameters from clones. These patterns of gene activation recapitulate the endogenous relative accumulation of Drm, Bowl and Eyg. Though
the cell-autonomous induction of Bowl and Eyg required Bowl function, the non-autonomous effects were Bowl-independent. These data suggest that Drm
promotes a long range signal to pattern and expand the anterior part of the notum. Loss of function studies indicate that one or more proteins act redundantly
with Drm to promote Bowl and Eyg, while ectopic expression reveals that Odd and Sob are each sufficient to promote Bowl accumulation. By contrast, at
L2 we find that Bowl is uniquely necessary to promote Bar-h expression to pattern the anterior notum. Our data suggest that Odd-skipped genes exhibit both
unique and complementary functions to elaborate pattern across a field of cells, and suggest an important role for the anterior notum margin in coordinating
growth and patterning across the notum AP axis.
717C
A calibrated examination of the influence of dosage variance in
brinker
on multivariate wingshape.
Anne Sonnenschein, David Arnosti, Ian Dworkin.
Michigan State University, East Lansing, MI.
Cis-regulatory regions control the gene-dosage output of protein-coding genes. Variation in these regulatory regions is prevalent, and has been proposed to
contribute to within-species phenotypic differences as well as the heritability of complex diseases. Mutations in cis-regulatory regions can have little to no
effect, or induce dramatic mutant phenotypes depending on the location and severity of the molecular change. There is no clear gradient of gene dosage
between natural phenotypic variation and clear mutational effects, therefore, a quantitative exploration of this phenomenon is required to understand how
genetic systems respond to this variation. . The transcriptional repressor Brinker plays a pivotal role in
Drosophila melanogaster
wing development. Its
regulatory region is complex, including multiple regulatory modules with overlapping function. This built in redundancy might indicate a system that is
highly sensitive to subtle variation in gene dosage. We are conducting a series of experiments to establish a ‘gene dosage series’, to demonstrate the range of
variation that can be expected from varying degrees of up-regulation and down-regulation of Brinker. We are using the power of multivariate analysis of
wing-shape is sufficiently sensitive to capture small differences in effect-size. Our study will provide a framework for later classification of
brinker
regulatory mutant alleles and mapping of contributions by within-species variation to phenotype.
718A
Identification of BMP target genes in the Drosophila larval wing precursor.
Alexander Springhorn
1
, Milica Jevtic
1
, Marco Blanchette
2
, Britta
Hartmann
3
, Giorgos Pyrowolakis
1
. 1) Department of Developmental Biology, Institute of Biology 1, Freiburg, Germany; 2) Stowers Institute for Medical
Research, Kansas City, USA; 3) Center for Biological Systems Analysis (ZBSA), Freiburg, Germany.
BMPs are secreted signaling proteins which are able to spread from their site of secretion into non-expressing tissue. In the larval precursor of the fly’s
wing the Drosophila BMP ligand Dpp forms a long-range morphogen gradient. BMP signaling along this gradient is needed for the growth and patterning of
the organ as well as for cell survival, maintenance of epithelial integrity and - by means of feed-back regulation - proper formation of the BMP signaling
activity gradient itself. We aimed at identifying new BMP target genes which mediate such functions. To this end, we hyper-activated or blocked the BMP
pathway in a spatially and temporarily controlled manner and assessed transcriptome changes by RNA-sequencing. Expression-profiling allowed us to
reduce the high number of significantly responding targets to a handful of candidates which display a consistent response at all analyzed conditions. We will
present results from the ongoing functional analysis of shortlisted genes and report on cis-regulatory modules that mediate their BMP-signaling
responsiveness.