The products of the Polycomb group of genes are cooperatively involved in repressing expression of homeotic selector genes outside of their appropriate anterior/posterior boundaries. Loss of maternal and/or zygotic function of Polycomb group genes results in the ectopic expression of both Antennapedia Complex and Bithorax Complex genes. The products of the trithorax group of genes are cooperatively involved in maintaining active expression of homeotic selector genes within their appropriate anterior/posterior boundaries. Loss of maternal and/or zygotic function of trithorax group genes results in reduced expression of both Antennapedia Complex and Bithorax Complex genes. Although Enhancer of zeste has been classified as a member of the Polycomb group, in this paper we show that Enhancer of zeste can also be classified as a member of the trithorax group. The requirement for Enhancer of zeste activity as either a trithorax group or Polycomb group gene depends on the homeotic selector gene locus as well as on spatial and temporal cues.

Reference

Beachy
P. A.
,
Krasnow
M. A.
,
Gavis
E. R.
,
Hogness
D. S.
(
1988
)
An Ultrabithorax protein binds sequences near its own and the Antennapedia P1 promoters.
Cell
55
,
1069
81
Breen
T. R.
,
Harte
P. J.
(
1993
)
trithorax regulates multiple homeotic genes in the bithorax and Antennapedia complexes and exerts different tissue specific, parasegment specific and promoter specific effects on each.
Development
117
,
119
134
Brower
D.
(
1986
)
engrailed gene expression in Drosophila imaginal discs.
EMBO J
5
,
2649
2656
Busturia
A.
,
Morata
G.
(
1988
)
Ectopic expression of homeotic genes caused by the elimination of the Polycomb gene in Drosophila imaginal epidermis.
Development
104
,
713
720
Campbell
R. B.
,
Sinclair
D. A. R.
,
Couling
M.
,
Brock
H. W.
(
1995
)
Genetic interactions and dosage effects of Polycomb group genes of Drosophila.
Mol. Gen. Genet
246
,
291
300
DeCammilis
M.
,
Cheng
N.
,
Pierre
D.
,
Brock
H. W.
(
1992
)
The polycombeotic gene of Drosophila encodes a chromatin protein that shares polytene chromosome-binding sites with Polycomb.
Gene Dev
6
,
223
232
Dingwall
A. S. K.
,
Beek
S. J.
,
McCallum
C. M.
,
Tamkun
J. W.
,
Kalpana
G. V.
,
Goff
S. P.
,
Scott
M. P.
(
1995
)
The Drosophila snr1 and brm proteins are related to SWI/SNF proteins and are components of a large protein complex.
Mol. Biol. Cell
6
,
777
791
Duncan
I.
(
1982
)
Polycomb-like: a gene that appears to be required for the normal expression of the bithorax and Antennapedia gene complexes of Drosophila melanogaster.
Genetics
102
,
49
70
Franke
A.
,
DeCamillis
M.
,
Zink
D.
,
Cheng
N.
,
Brock
H. W.
,
Paro
R.
(
1992
)
Polycomb and polyhomeotic are constituents of multimeric protein complex in chromatin of Drosophila melanogaster.
EMBO J
11
,
2941
2950
Glicksman
M. A.
,
Brower
D.
(
1988
)
Expression of Sex combs reduced Protein in Drosophila larvae.
Dev. Biol
127
,
113
118
Hafen
E.
,
Levine
M.
,
Gehring
W. J.
(
1984
)
Regulation of Antennapedia transcript distribution by the Bithorax complex in Drosophila.
Nature
307
,
287
289
Ingham
P. W.
(
1985
)
A clonal analysis of the requirements for the trithorax gene in the diversification of segments in Drosophila.
J. Emb. Exp. Morph.,
89
,
349
65
Ingham
P. W.
,
Whittle
R.
(
1980
)
Trithorax: a new homeotic mutation of Drosophila melanogaster causing transformations of abdominal and thoracic imaginal segments. I. Putative role during embryogenesis.
Mol. Gen. Genet
179
,
607
614
Irvine
K. D.
,
Botas
J.
,
Jha
S.
,
Mann
R. S.
,
Hogness
D. S.
(
1993
)
Negative auto-regulation by Ultrabithorax controls the level and pattern of its expression.
Development
117
,
387
399
Jurgens
G.
(
1985
)
A group of genes controlling the spatial expression of the bithorax complex in Drosophila.
Nature
316
,
153
155
Jones
R. S.
,
Gelbart
W. M.
(
1990
)
Genetic analysis of the Enhancer of zeste locus and its role in gene regulation in Drosophila melanogaster.
Genetics
126
,
185
199
Jones
R. S.
,
Gelbart
W. M.
(
1993
)
The Drosophila Polycomb-group gene Enhancer of zeste contains a region with sequence similarity to trithorax.
Mol. Cell. Biol
13
,
6357
6366
Kalisch
W.-E.
,
Rasmuson
B.
(
1974
)
Changes in zeste phenotype induced by autosomal mutations in Drosophila melanogaster.
Hereditas
78
,
97
104
Kuzin
B.
,
Tillib
S.
,
Sedkov
Y.
,
Mizrokhi
L.
,
Mazo
A.
(
1994
)
The trithorax gene encodes a chromosomal protein and directly regulates the region-specific homeotic gene fork head.
Genes Dev
8
,
2487
2490
LaJeunesse
D.
,
Shearn
A.
(
1995
)
Trans-regulation of thoracic homeotic selector genes of the Antennapedia and bithorax complexes by the trithorax group genes absent small and homeotic discs 1 and 2.
Mech. Dev
53
,
123
139
Lamka
M. L.
,
Boulet
A. M.
,
Sakonju
S.
(
1992
)
Ectopic expression of UBX and ABD-B proteins during Drosophila embryogenesis: competition, not a functional hierarchy, explains phenotypic suppression.
Development
116
,
841
54
Orlando
V.
,
Paro
R.
(
1993
)
Mapping Polycomb-repressed domains in the Bithorax Complex using in vivo formaldehyde cross-linked chromatin.
Cell
75
,
1187
1198
Paro
R.
(
1990
)
Imprinting a determined state into the chromatin of Drosophila.
Trends Genet
6
,
416
421
Paro
R.
(
1993
)
Mechanisms of heritable gene repression during development of Drosophila.
Curr. Opin. Cell Biol
5
,
999
1005
Pelegri
F.
,
Lehmann
R.
(
1994
)
A role of Polycomb group genes in the regulation of gap gene expression in Drosophila.
Genetics,
136
,
1341
1353
Phillips
M.
,
Shearn
A.
(
1990
)
Mutations in polycombeotic, a Drosophila Polycomb-Group gene, cause a wide range of maternal and zygotic phenotypes.
Genetics
125
,
91
101
Rastelli
L.
,
Chan
C. S.
,
Pirrota
V.
(
1993
)
Related chromosome binding sites for zeste, Suppressors of zeste and Polycomb group proteins in Drosophila and their dependence on Enhancer of zeste action.
EMBO J
12
,
1513
1522
Reuter
G.
,
Spierer
P.
(
1992
)
Position effect variegation and chromosomal proteins.
BioEssays
14
,
605
612
Sauer
F.
,
Fondell
J. D.
,
Ohkuma
Y.
,
Roeder
R. G.
,
Jäckle
H.
(
1995
)
Control of transcription by Kruppel through interactions with TFIIB and TFIIE.
Nature
375
,
162
164
Shearn
A.
(
1989
)
The ash1, ash2 and trithorax genes of Drosophila are functionally related.
Genetics
121
,
517
525
Shearn
A.
,
Hersperger
G.
,
Hersperger
E.
(
1978
)
Genetic analysis of two allelic temperature-sensitive mutants of Drosophila melanogaster both of which are zygotic and maternal-effect lethals.
Genetics
89
,
341
353
Shearn
A.
,
Rice
T.
,
Garen
A.
,
Gehring
W.
(
1971
)
Imaginal disc abnormalities in lethal mutants of Drosophila.
Proc. Natl. Acad. Sci. USA
68
,
2695
2698
Simon
J.
,
Change
A.
,
Bender
W.
(
1992
)
Ten different Polycomb group genes are required for spatial control of the abdA and AbdB homeotic products.
Development
114
,
493
505
Stassen
M. J.
,
Bailey
D.
,
Fox
S.
,
Chinwalla
V.
,
Harte
P. J.
(
1995
)
The Drosophilatrithorax proteins contain a novel variant of the nuclear receptor type DNA binding domain and an ancient conserved motif found in other chromosomal proteins.
Mech. Dev
52
,
1
15
Struhl
G.
,
Akam
M.
(
1985
)
Altered distributions of Ultrabithorax transcripts in extra sex combs mutant embryos of Drosophila.
EMBO J
4
,
3259
3264
Tamkun
J. W.
,
Deuring
R.
,
Scott
M. P.
,
Kissenger
M.
,
Pattatucci
A. M.
,
Kaufman
T. C.
,
Kennison
J. A.
(
1992
)
brahma: a regulator of Drosophila homeotic genes structurally related to the yeast transcriptional activator SNF2/SWI2.
Cell
68
,
561
572
Tripoulas
N. A.
,
Hersperger
E.
,
LaJeunesse
D.
,
Shearn.
A.
(
1994
)
Molecular genetic analysis of the Drosophilamelanogaster gene absent, small or homeotic imaginal discs 1 (ash 1).
Genetics
137
,
1027
1038
Tschiersch
B.
,
Hofmann
A.
,
Krauss
V.
,
Dorn
R.
,
Korge
G.
,
Reuter
G.
(
1994
)
The protein encoded by the Drosophila position effect variegation suppressor gene Su(var)3-9 combines domains of antagonistic regulators of homeotic gene complexes.
EMBO J
13
,
3822
3831
Wedeen
C.
,
Harding
K.
,
Levine
M.
(
1986
)
Spatial regulation of Antennapedia and bithorax gene expression by the Polycomb locus in Drosophila.
Cell,
44
,
739
748
White
R. A.
,
Wilcox
M.
(
1984
)
Protein products of the bithorax complex in Drosophila.
Cell
39
,
163
171
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