TY - JOUR
T1 - Drosophila eggshell is patterned by sequential action of feedforward and feedback loops
AU - Yakoby, Nir
AU - Lembong, Jessica
AU - Schüpbach, Trudi
AU - Shvartsman, Stanislav Y.
PY - 2008/1
Y1 - 2008/1
N2 - During Drosophila oogenesis, patterning activities of the EGFR and Dpp pathways specify several subpopulations of the follicle cells that give rise to dorsal eggshell structures. The roof of dorsal eggshell appendages is formed by the follicle cells that express Broad (Br), a zinc-finger transcription factor regulated by both pathways. EGFR induces Br in the dorsal follicle cells. This inductive signal is overridden in the dorsal midline cells, which are exposed to high levels of EGFR activation, and in the anterior cells, by Dpp signaling. We show that the resulting changes in the Br pattern affect the expression of Dpp receptor thickveins (tkv), which is essential for Dpp signaling. By controlling tkv, Br controls Dpp signaling in late stages of oogenesis and, as a result, regulates its own repression in a negative-feed back loop. We synthesize these observations into a model, whereby the dynamics of Br expression are driven by the sequential action of feedforward and feedback loops. The feedforward loop controls the spatial pattern of Br expression, while the feedback loop modulates this pattern in time. This mechanism demonstrates how complex patterns of gene expression can emerge from simple inputs, through the interaction of regulatory network motifs.
AB - During Drosophila oogenesis, patterning activities of the EGFR and Dpp pathways specify several subpopulations of the follicle cells that give rise to dorsal eggshell structures. The roof of dorsal eggshell appendages is formed by the follicle cells that express Broad (Br), a zinc-finger transcription factor regulated by both pathways. EGFR induces Br in the dorsal follicle cells. This inductive signal is overridden in the dorsal midline cells, which are exposed to high levels of EGFR activation, and in the anterior cells, by Dpp signaling. We show that the resulting changes in the Br pattern affect the expression of Dpp receptor thickveins (tkv), which is essential for Dpp signaling. By controlling tkv, Br controls Dpp signaling in late stages of oogenesis and, as a result, regulates its own repression in a negative-feed back loop. We synthesize these observations into a model, whereby the dynamics of Br expression are driven by the sequential action of feedforward and feedback loops. The feedforward loop controls the spatial pattern of Br expression, while the feedback loop modulates this pattern in time. This mechanism demonstrates how complex patterns of gene expression can emerge from simple inputs, through the interaction of regulatory network motifs.
KW - Cell signaling
KW - Drosophila
KW - Epithelial patterning
KW - Feedforward control
KW - Pattern formation
UR - http://www.scopus.com/inward/record.url?scp=38949210684&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=38949210684&partnerID=8YFLogxK
U2 - 10.1242/dev.008920
DO - 10.1242/dev.008920
M3 - Article
C2 - 18077592
AN - SCOPUS:38949210684
SN - 0950-1991
VL - 135
SP - 343
EP - 351
JO - Journal of Embryology and Experimental Morphology
JF - Journal of Embryology and Experimental Morphology
IS - 2
ER -