Although many of the genes that pattern the segmented body plan of the Drosophila embryo are known, there remains much to learn in terms of how these genes and their products interact with one another. Like many of these gene products, the protein encoded by the pair-rule gene odd-skipped (Odd) is a DNA-binding transcription factor. Genetic experiments have suggested several candidate target genes for Odd, all of which appear to be negatively regulated. Here we use pulses of ectopic Odd expression to test the response of these and other segmentation genes. The results are complex, indicating that Odd is capable of repressing some genes wherever and whenever Odd is expressed, while the ability to repress others is temporally or spatially restricted. Moreover, one target gene, fushi tarazu, is both repressed and activated by Odd, the outcome depending upon the stage of development. These results indicate that the activity of Odd is highly dependent upon the presence of cofactors and/or overriding inhibitors. Based on these results, and the segmental phenotypes generated by ectopic Odd, we suggest a number of new roles for Odd in the patterning of embryonic segments. These include gap-, pair-rule- and segment polarity-type functions.

REFERENCES

Akimaru
H.
,
Hou
D. X.
,
Ishii
S.
(
1997
)
Drosophila CBP is required for dorsal-dependent twist gene expression.
Nat. Genet
17
,
211
214
Baumgartner
S.
,
Noll
M.
(
1990
)
Network of interactions among pair-rule genes regulating paired expression during primordial segmentation of Drosophila.
Mech. Dev
33
,
1
18
Carroll
S. B.
,
Scott
M. P.
(
1986
)
Zygotically active genes that affect the spatial expression of the fushi tarazu segmentation gene during early Drosophila embryogenesis.
Cell
45
,
113
26
Coulter
D. E.
,
Wieschaus
E.
(
1988
)
Gene activities and segmental patterning in Drosophila: analysis of odd-skipped and pair-rule double mutants.
Genes Dev
2
,
1812
23
Coulter
D. E.
,
Swaykus
E. A.
,
Beran-Koehn
M. A.
,
Goldberg
D.
,
Wieschaus
E.
,
Schedl
P.
(
1990
)
Molecular analysis of odd-skipped, a zinc finger encoding segmentation gene with a novel pair-rule expression pattern.
EMBO J
9
,
3795
804
DiNardo
S.
,
O'Farrell
P. H.
(
1987
)
Establishment and refinement of segmental pattern in the Drosophila embryo: spatial control of engrailed expression by pair-rule genes.
Genes Dev
1
,
1212
25
DiNardo
S.
,
Heemskerk
J.
(
1990
)
Molecular and cellular interactions responsible for intrasegmental patterning during Drosophila embryogenesis.
Sem. in Cell Biol
1
,
173
83
Engels
W. R.
,
Benz
W. K.
,
Preston
C. R.
,
Graham
P. L.
,
Phillis
R. W.
,
Robertson
H. M.
(
1987
)
Somatic effects of P element activity in Drosophilamelanogaster: pupal lethality.
Genetics
117
,
745
57
Fisher
A. L.
,
Caudy
M.
(
1998
)
Groucho proteins: transcriptional corepressors for specific subsets of DNA-binding transcription factors in vertebrates and invertebrates.
Genes Dev
13
,
1931
1940
Florence
B.
,
Guichet
A.
,
Ephrussi
A.
,
Laughon
A.
(
1997
)
Ftz-F1 is a cofactor in Ftz activation of the Drosophilaengrailed gene.
Development
124
,
839
47
Frasch
M.
,
Warrior
R.
,
Tugwood
J.
,
Levine
M.
(
1988
)
Molecular analysis of even-skipped mutants in Drosophila development.
Genes Dev
2
,
1824
1838
Gergen
P. J.
,
Wieschaus
E.
(
1985
)
The localized requirements for a gene affecting segmentation in Drosophila: analysis of larvae mosaic for runt.
Dev. Biol
109
,
321
335
Gutjahr
T.
,
Frei
E.
,
Noll
M.
(
1993
)
Complex regulation of early paired expression: initial activation by gap genes and pattern modulation by pair-rule genes.
Development
117
,
609
23
Heemskerk
J.
,
DiNardo
S.
,
Kostriken
R.
,
O'Farrell
P. H.
(
1991
)
Multiple modes of engrailed regulation in the progression towards cell fate determination.
Nature
352
,
404
10
Howard
K.
,
Ingham
P.
(
1986
)
Regulatory interactions between the segmentation genes fushi tarazu, hairy, and engrailed in the Drosophila blastoderm.
Cell
44
,
949
57
Howard
K.
,
Ingham
P.
,
Rushlow
C.
(
1988
)
Region-specific alleles of the segmentaion gene hairy.
Genes Dev
2
,
1037
1046
Ingham
P. W.
(
1988
)
The molecular genetics of embryonic pattern formation in Drosophila.
Nature
335
,
25
34
Ingham
P. W.
,
Baker
N. E.
,
Marinez-Arias
A.
(
1988
)
Regulation of segment polarity genes in the Drosophila blastodermby fushi tarazu and even-skipped.
Nature
331
,
73
75
Ingham
P. W.
,
Howard
K. R.
,
Ish-Horowicz
D.
(
1988
)
Transcription pattern of the Drosophila segmentation gene hairy.
Nature
318
,
439
445
Klingler
M.
,
Soong
J.
,
Butler
B.
,
Gergen
J. P.
(
1996
)
Disperse versus compact elements for the regulation of runt stripes in Drosophila.
Dev. Biol
177
,
73
84
Lawrence
P. A.
,
Johnston
P.
,
Macdonald
P.
,
Struhl
G.
(
1987
)
Borders of parasegments in Drosophila embryos are delimited by the fushi tarazu and even-skipped genes.
Nature
328
,
440
2
Lehmann
R.
,
Tautz
D.
(
1994
)
In situ hybridization to RNA.
Methods Cell Biol
44
,
575
98
Manoukian
A. S.
,
Krause
H. M.
(
1992
)
Concentration-dependent activities of the even-skipped protein in Drosophila embryos.
Genes Dev
6
,
1740
51
Manoukian
A. S.
,
Krause
H. M.
(
1993
)
Control of segmental asymmetry in Drosophila embryos.
Development
118
,
785
96
Martinez-Arias
A.
,
Lawrence
P. A.
(
1985
)
Parasegments and compartments in the Drosophila embryo.
Nature
313
,
639
42
Martinez-Arias
A.
,
Baker
N. E.
,
Ingham
P. W.
(
1988
)
Role of segment polarity genes in the definition and maintenance of cell states in the Drosophila embryo.
Development
103
,
157
70
Mullen
J. R.
,
DiNardo
S.
(
1995
)
Establishing parasegments in Drosophila embryos: roles of the odd-skipped and naked genes.
Dev. Biol
169
,
295
308
Nibu
Y.
,
Zhang
H.
,
Levine
M.
(
1998
)
Interaction of short range repressors with drosohila CtBP in the embryo.
Science
280
,
101
104
Nusslein-Volhard
C.
,
Wieschaus
E.
(
1980
)
Mutations affecting segment number and polarity in Drosophila.
Nature
287
,
795
801
Nusslein-Volhard
C.
,
Kluding
H.
,
Jurgens
G.
(
1985
)
Genes affecting the segmental subdivision of the Drosophila embryo.
Cold Spring Harbor Symp. Quant. Biol
50
,
145
154
Pankratz
M. J.
,
Jackle
H.
(
1990
)
Making stripes in the Drosophila embryo.
Trends Genet
6
,
287
92
Robertson
H. M.
,
Preston
C. R.
,
Phillis
R. W.
,
Johnson-Schlitz
D. M.
,
Benz
W. K.
,
Engels
W. R.
(
1988
)
A stable genomic source of P element transposase in Drosophila melanogaster.
Genetics
118
,
461
70
Spradling
A. C.
,
Rubin
G. M.
(
1982
)
Transposition of cloned P elements into Drosophila germ line chromosomes.
Science
218
,
341
7
Tautz
D.
,
Pfeifle
C.
(
1989
)
A non-radioactive in situ hybridization method for the localization of specific RNAs in Drosophila embryos reveals translational control of the segmentation gene hunchback.
Chromosoma
98
,
81
5
Tsai
C.
,
Gergen
J. P.
(
1994
)
Gap gene properties of the pair-rule gene runt during Drosophila segmentation.
Development
120
,
1671
83
Yu
Y.
,
Pick
L.
(
1995
)
Non-periodic cues generate seven ftz stripes in the Drosophila embryo.
Mech. Dev
50
,
163
75
This content is only available via PDF.