The Drosophila BMP homolog DPP can function as a morphogen, inducing multiple cell fates across a developmental field. However, it is unknown how graded levels of extracellular DPP are interpreted to organize a sharp boundary between different fates. Here we show that opposing DPP and EGF signals set the boundary for an ovarian follicle cell fate. First, DPP regulates gene expression in the follicle cells that will create the operculum of the eggshell. DPP induces expression of the enhancer trap reporter A359 and represses expression of bunched, which encodes a protein similar to the mammalian transcription factor TSC-22. Second, DPP signaling indirectly regulates A359 expression in these cells by downregulating expression of bunched. Reduced bunched function restores A359 expression in cells that lack the Smad protein MAD; ectopic expression of BUNCHED suppresses A359 expression in this region. Importantly, reduction of bunched function leads to an expansion of the operculum and loss of the collar at its boundary. Third, EGF signaling upregulates expression of bunched. We previously demonstrated that the bunched expression pattern requires the EGF receptor ligand GURKEN. Here we show that activated EGF receptor is sufficient to induce ectopic bunched expression. Thus, the balance of DPP and EGF signals sets the boundary of bunched expression. We propose that the juxtaposition of cells with high and low BUNCHED activity organizes a sharp boundary for the operculum fate.

REFERENCES

Brand
A. H.
,
Perrimon
N.
(
1993
)
Targeted gene expression as a means of altering cell fates and generating dominant phenotypes.
Development
118
,
401
415
Campbell
G.
,
Tomlinson
A.
(
1999
)
Transducing the Dpp morphogen gradient in the wing of Drosophila: regulation of Dpp targets by brinker.
Cell
96
,
553
562
de Celis
J.
(
1997
)
Expression and function of decapentaplegic and thick veins during differentiation of the veins in the Drosophila wing.
Development
124
,
1007
1018
Deng
W. M.
,
Bownes
M.
(
1997
)
Two signalling pathways specify localised expression of the Broad-Complex in Drosophila eggshell patterning and morphogenesis.
Development
124
,
4639
4647
Dobens
L.
,
Hsu
T.
,
Twombly
V.
,
Gelbart
W.
,
Raftery
L.
,
Kafatos
F.
(
1997
)
The Drosophila bunched gene is a homologue of the growth factor stimulated mammalian TSC-22 sequence and is required during oogenesis.
Mech. Dev
65
,
197
208
Golic
K.
(
1991
)
Site-specific recombination between homologous chromosomes in Drosophila.
Science
252
,
958
961
Grossniklaus
U.
,
Bellen
H. J.
,
Wilson
C.
,
Gehring
W. J.
(
1989
)
P-element-mediated enhancer detection applied to the study of oogenesis in Drosophila.
Development
107
,
189
200
Haerry
T.
,
Khalsa
O.
,
O'Connor
M.
,
Wharton
K.
(
1998
)
Synergistic signaling by two BMP ligands through the SAX and TKV receptors controls wing growth and patterning in Drosophila.
Development
125
,
3977
3987
Hamil
K. G.
,
Hall
S. H.
(
1994
)
Cloning of rat Sertoli cell follicle-stimulating hormone primary response complementary deoxyribonucleic acid: regulation of TSC-22 gene expression.
Endocrinology
134
,
1205
1212
Hogan
B. L. M.
(
1996
)
Bone morphogenetic proteins: multifunctional regulators of vertebrate development.
Genes Dev
10
,
1580
1594
Jazwinska
A.
,
Kirov
N.
,
Wieschaus
E.
,
Roth
S.
,
Rushlow
C.
(
1999
)
The Drosophila gene brinker reveals a novel mechanism of Dpp target gene regulation.
Cell
96
,
563
573
Kania
A.
,
Salzberg
A.
,
Bhat
M.
,
D'Evelyn
D.
,
He
Y.
,
Kiss
I.
,
Bellen
H. J.
(
1995
)
P-element mutations affecting embryonic peripheral nervous system development in Drosophila melanogaster.
Genetics
139
,
1663
1678
Kester
H. A.
,
Blanchetot
C.
,
den Hertog
J.
,
van der Saag
P. T.
,
van der Burg
B.
(
1999
)
Transforming growth factor-beta-stimulated clone-22 is a member of a family of leucine zipper proteins that can homo-and heterodimerize and has transcriptional repressor activity [In Process Citation].
J Biol Chem
274
,
27439
27447
Kretzschmer
M.
,
Doody
J.
,
Massague
J.
(
1997
)
Opposing BMP and EGF signalling pathways converge on the TGF-family mediator Smad1.
Nature
389
,
618
622
Minami
M.
,
Kinoshita
N.
,
Kamoshida
Y.
,
Tanimoto
H.
,
Tabata
T.
(
1999
)
brinker is a target of Dpp in Drosophila that negatively regulates Dpp-dependent genes.
Nature
398
,
242
246
Neubuser
A.
,
Peters
H.
,
Balling
R.
,
Martin
G. R.
(
1997
)
Antagonistic interactions between FGF and BMP signaling pathways: a mechanism for positioning the sites of tooth formation.
Cell
90
,
247
255
Neuman-Silberberg
F. S.
,
Schupbach
T.
(
1993
)
The Drosophila dorsoventral patterning gene gurken produces a dorsally localized RNA and encodes a TGF-like protein.
Cell
75
,
165
174
Neumann
C.
,
Cohen
S.
(
1997
)
Morphogens and pattern formation.
Bioessays
19
,
721
729
Newfeld
S. J.
,
Mehra
A.
,
Singer
M. A.
,
Wrana
J. L.
,
Attisano
L.
,
Gelbart
W. M.
(
1997
)
Mothers against dpp participates in a DPP/TGF-responsive serine-threonine kinase signal transduction cascade.
Development
124
,
3167
3176
Niswander
L.
,
Martin
G. R.
(
1993
)
FGF-4 and BMP-2 have opposite effects on limb growth.
Nature
361
,
68
71
Noramly
S.
,
Morgan
B. A.
(
1998
)
BMPs mediate lateral inhibition at successive stages in feather tract development.
Development
125
,
3775
3787
Ohta
S.
,
Shimekaka
Y.
,
Nagata
K.
(
1996
)
Molecular cloning and characterization of a transcription factor for the C-type natriuretic peptide gene promoter.
Eur. J. Biochem
242
,
460
466
Padgett
R. W.
,
St. Johnston
D.
,
Gelbart
W. M.
(
1987
)
A transcript from a Drosophila pattern gene predicts a protein homologous to the transforming growth factor-gene family.
Nature
325
,
81
84
Perrimon
N.
,
Lanjun
A.
,
Arnold
C.
,
Noll
E.
(
1996
)
Zygotic lethal mutations with maternal effect phenotypes in Drosophila melanogaster. II.Loci on the second and third chromosomes identified by P -element-induced mutations.
Genetics
144
,
1681
1692
Perrimon
N.
,
Perkins
L.
(
1997
)
There must be 50 ways to rule the signal: the case of the Drosophila EGF receptor.
Cell
89
,
13
16
Pignoni
F.
,
Zipursky
S. L.
(
1997
)
Induction of Drosophila eye development by Decapentaplegic.
Development
124
,
271
278
Price
J.
,
Clifford
R.
,
Schupbach
T.
(
1989
)
The maternal ventralizing locus torpedo is allelic to faint little ball, an embryonic lethal, and encodes the Drosophila EGF receptor homolog.
Cell
56
,
1085
1092
Queenan
A.
,
Ghabrial
A.
,
Schupbach
T.
(
1997
)
Ectopic activation of torpedo/Egfr, a Drosophila receptor tyrosine kinase, dorsalizes both the eggshell and the embryo.
Development
124
,
3871
3880
Raftery
L.
,
Sutherland
D.
(
1999
)
TGF-family signal transduction in Drosophila: from Mad to Smads.
Dev. Biol
210
,
251
268
Ray
R. P.
,
Schupbach
T.
(
1996
)
Intercellular signaling and the polarization of body axes during Drosophila oogenesis.
Genes Dev
10
,
1711
1723
Rubin
G. M.
,
Spradling
A. C.
(
1982
)
Genetic transformation of Drosophila with transposable element vectors.
Science
218
,
348
353
Sapir
A.
,
Schweitzer
R.
,
Shilo
B.-Z.
(
1998
)
Sequential activation of the EGF receptor pathway during Drosophila oogenesis establishes the dorsoventral axis.
Development
125
,
191
200
Schejter
E.
,
Shilo
B.-Z.
(
1989
)
The Drosophila EGF receptor homolog (DER) gene is allelic to faint little ball, a locus essential for embryonic development.
Cell
56
,
1093
1104
Schupbach
T.
(
1987
)
Germ line and soma cooperate during oogenesis to establish the dorsal/ventral pattern of egg shell and embryo in Drosophila melanogaster.
Cell
49
,
699
707
Seidel
G.
,
Adermann
K.
,
Schindler
T.
,
Ejchart
A.
,
Jaenicke
R.
,
Forssmann
W.-G.
,
Rösch
P.
(
1997
)
Solution structure of porcine delta sleep-inducing peptide immunoreactive peptide A homolog of the shortsighted gene product.
J. Biol. Chem
272
,
30918
30927
Sekelsky
J. J.
,
Newfeld
S. J.
,
Raftery
L. A.
,
Chartoff
E. H.
,
Gelbart
W. M.
(
1995
)
Genetic characterization and cloning of Mothers against dpp, a gene required for decapentaplegic function in Drosophila melanogaster.
Genetics
139
,
1347
1358
Shibanuma
M.
,
Kuroki
T.
,
Nose
K.
(
1992
)
Isolation of a gene encoding a putative leucine zipper structure that is induced by transforming growth factor1 and other growth factors.
J. Cell. Biol
267
,
10219
10224
Simon
J. A.
,
Sutton
C. A.
,
Lobell
R. B.
,
Galser
R. L.
,
Lis
J. T.
(
1985
)
Determinants of heat shock induced chromosome puffing.
Cell
40
,
805
817
Staehling-Hampton
K.
,
Hoffmann
F. M.
(
1994
)
Ectopic decapentaplegic in the Drosophila midgut alters the expression of five homeotic genes, dpp, and wingless, causing specific morphological defects.
Dev. Biol
164
,
502
512
Stroumbakis
N. D.
,
Li
Z.
,
Tolias
P. P.
(
1994
)
RNA-and single-stranded DNA-binding (SSB) proteins expressed during Drosophila melanogaster oogenesis: a homolog of bacterial and eukaryotic mitochondrial SSBs.
Gene
143
,
171
177
Szuts
D.
,
Eresh
S.
,
Bienz
M.
(
1998
)
Functional intertwining of Dpp and EGFR signaling during Drosophila endoderm induction.
Genes Dev
12
,
2022
2035
The-FlyBase-Consortium
(
1999
)
The FlyBase database of the Drosophila Genome Projects and community literature.
Nucleic Acids Res
27
,
85
88
Treisman
J. E.
,
Lai
Z.-C.
,
Rubin
G. M.
(
1995
)
shortsighted acts in the decapentaplegic pathway in Drosophila eye development and has homology to a mouse TGF--responsive gene.
Development
121
,
2835
2845
Twombly
V.
,
Blackman
R. K.
,
Jin
H.
,
Padgett
R. W.
,
Gelbart
W. M.
(
1996
)
The TGF-signaling pathway is required in Drosophila oogenesis.
Development
122
,
1555
1565
Wappner
P.
,
Gabay
L.
,
Shilo
B. Z.
(
1997
)
Interactions between the EGF receptor and DPP pathways establish distinct cell fates in the tracheal placodes.
Development
124
,
4707
4716
Wasserman
J.
,
Freeman
M.
(
1998
)
An autoregulatory cascade of EGF receptor signaling patterns the Drosophila egg.
Cell
95
,
355
364
Whitman
M.
(
1998
)
Smads and early developmental signaling by the TGFsuperfamily.
Genes Dev
12
,
2445
2462
Xu
T.
,
Rubin
G. M.
(
1993
)
Analysis of genetic mosaics in developing and adult Drosophila tissues.
Development
117
,
1223
1237
Zecca
M.
,
Basler
K.
,
Struhl
G.
(
1995
)
Sequential organizing activities of engrailed, hedgehog, and decapentaplegic in the Drosophila wing.
Development
121
,
2265
2278
This content is only available via PDF.