The trithorax group gene brahma (brm) encodes an activator of Drosophila homeotic genes that functions as the ATPase subunit of a large protein complex. To determine if BRM physically interacts with other trithorax group proteins, we purified the BRM complex from Drosophila embryos and analyzed its subunit composition. The BRM complex contains at least seven major polypeptides. Surprisingly, the majority of the subunits of the BRM complex are not encoded by trithorax group genes. Furthermore, a screen for enhancers of a dominant-negative brm mutation identified only one trithorax group gene, moira (mor), that appears to be essential for brm function in vivo. Four of the subunits of the BRM complex are related to subunits of the yeast chromatin remodeling complexes SWI/SNF and RSC. The BRM complex is even more highly related to the human BRG1 and hBRM complexes, but lacks the subunit heterogeneity characteristic of these complexes. We present biochemical evidence for the existence of two additional complexes containing trithorax group proteins: a 2 MDa ASH1 complex and a 500 kDa ASH2 complex. These findings suggest that BRM plays a role in chromatin remodeling that is distinct from the function of most other trithorax group proteins.
REFERENCES
Adamson
A. L.
, Shearn
A.
(1996
) Molecular genetic analysis of Drosophila ash2, a member of the trithorax group required for imaginal disc pattern formation.
Genetics
144
, 621
–633
Altschul
S. F.
, Gish
W.
, Miller
W.
, Myers
E. W.
, Lipman
D. J.
(1990
) Basic local alignment search tool.
J. Mol. Biol
215
, 403
–410
Brizuela
B. J.
, Kennison
J. A.
(1997
) The Drosophila homeotic gene moira regulates expression of engrailed and HOM genes in imaginal tissues.
Mech. Dev
65
, 209
–220
Brizuela
B.J.
, Elfring
L.K.
, Ballard
J.
, Tamkun
J.W.
, Kennison
J.A.
(1994
) Genetic analysis of the brahma gene of Drosophila melanogaster and polytene subdivisions 72AB.
Genetics
137
, 803
–813
Budnik
V.
, White
K.
(1987
) Genetic dissection of dopamine and serotonin synthesis in the nervous system of Drosophila melanogaster.
J. Neurogenet
4
, 309
–314
Cairns
B. R.
, Levinson
R. S.
, Yamamoto
K. R.
, Kornberg
R. D.
(1996
) Essential role of Swp73p in the function of yeast Swi/Snf complex.
Genes Dev
10
, 2131
–2144
Cairns
B. R.
, Lorch
Y.
, Li
Y.
, Zhang
M.
, Lacomis
L.
, Erdjument
B. H.
, Tempst
P.
, Du
J.
, Laurent
B.
, Kornberg
R. D.
(1996
) RSC, an essential, abundant chromatin-remodeling complex.
Cell
87
, 1249
–1260
Côte
J.
, Quinn
J.
, Workman
J. L.
, Peterson
C. L.
(1994
) Stimulation of GAL4 derivative binding to nucleosomal DNA by the yeast SWI/SNF complex.
Science
265
, 53
–60
Dingwall
A. 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 yeast SWI/SNF proteins and are components of a large protein complex.
Mol. Biol. Cell
6
, 777
–791
Elfring
L. K.
, Daniel
C.
, Papoulas
O.
, Deuring
R.
, Sarte
M.
, Moseley
S.
, Beek
S. J.
, Waldrip
W. R.
, Daubresse
G.
, DePace
A.
, Kennison
J. A.
, Tamkun
J.W.
(1998
) Genetic analysis of brahma: the Drosophila homolog of the yeast chromatin remodeling factor SWI2/SNF2.
Genetics
148
, 251
–265
Elfring
L. K.
, Deuring
R.
, McCallum
C. M.
, Peterson
C. L.
, Tamkun
J. W.
(1994
) Identification and characterization of Drosophila relatives of the yeast transcriptional activator SNF2/SWI2.
Mol. Cell Biol
14
, 2225
–2234
Farkas
G.
, Gausz
J.
, Galloni
M.
, Reuter
G.
, Gyurkovics
H.
, Karch
F.
(1994
) The Trithorax-like gene encodes the Drosophila GAGA factor.
Nature
371
, 806
–808
Franke
A.
, Decamillis
M.
, Zink
D.
, Cheng
N. S.
, Brock
H. W.
, Paro
R.
(1992
) Polycomb and polyhomeotic are constituents of a multimeric protein complex in chromatin of Drosophila melanogaster.
EMBO J
11
, 2941
–2950
Frankel
S.
, Heintzelman
M. B.
, Artavanis-Tsakonas
S.
, Mooseker
M.S.
(1994
) Identification of a divergent actin-related protein in Drosophila.
J. Mol. Biol
235
, 1351
–1356
Frankel
S.
, Sigel
E. A.
, Craig
C.
, Elgin
S. C. R.
, Mooseker
M. S.
, Artavanis-Tsakonas
S.
(1997
) An actin-related protein in Drosophila colocalizes with heterochromatin protein 1 in pericentric heterochromatin.
J Cell Sci
110
, 1999
–2012
Gish
W.
, States
D.J.
(1993
) Identification of protein coding regions by database similarity search.
Nat. Genet
3
, 266
–72
Hirschhorn
J.
, Brown
S.
, Clark
C.
, Winston
F.
(1992
) Evidence that SNF2/SWI2 and SNF5 activate transcription in yeast by altering chromatin structure.
Genes Dev
6
, 2288
–2298
Jiang
Y. W.
, Stillman
D. J.
(1996
) Epigenetic effects on yeast transcription caused by mutations in an actin-related protein present in the nucleus.
Genes Dev
10
, 604
–619
Jones
C. A.
, Ng
J.
, Peterson
A. J.
, Morgan
K.
, Simon
J.
, Jones
R. S.
(1998
) The Drosophila esc and E(z) proteins are direct partners in Polycomb group-mediated repression.
Mol. Cell Biol
18
, 2825
–2834
Kaufman
T. C.
, Seeger
M. A.
, Olsen
G.
(1990
) Molecular and genetic organization of the Antennapedia gene complex of Drosophila melanogaster.
Adv. Genet
27
, 309
–362
Kennison
J. A.
(1995
) The Polycomb and trithorax group proteins of Drosophila: trans-regulators of homeotic gene function.
Annu. Rev. Genet
29
, 289
–303
Kennison
J. A.
, Tamkun
J. W.
(1988
) Dosage-dependent modifiers of Polycomb and Antennapedia mutations in Drosophila.
Proc. Natl. Acad. Sci. USA
85
, 8136
–8140
Khavari
P. A.
, Peterson
C. L.
, Tamkun
J. W.
, Mendel
D. B.
, Crabtree
G. R.
(1993
) BRG1 contains a conserved domain of the SWI2/SNF2 family necessary for normal mitotic growth and transcription.
Nature
366
, 170
–174
Kyba
M.
, Brock
H. W.
(1998
) The Drosophila Polycomb group protein Psc contacts ph and Pc through specific conserved domains.
Mol. Cell. Biol
18
, 2712
–2720
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
Lane
W. S.
, Galat
A.
, Harding
M. W.
, Schreiber
S. L.
(1991
) Complete amino acid sequence of the FK506 and rapamycin binding protein, FKBP, isolated from calf thymus.
J. Protein Chem
10
, 151
–160
Muchardt
C.
, Sardet
C.
, Bourachot
B.
, Onufryk
C.
, Yaniv
M.
(1995
) A human protein with homology to Saccharomyces cerevisiae SNF5 interacts with the potential helicase hbrm.
Nucleic Acids Res
23
, 1127
–1132
Nash
H. M.
, Bruner
S. D.
, Scharer
O. D.
, Kawate
T.
, Addona
T. A.
, Spooner
E.
, Lane
W.
, Verdine
G. L.
(1996
) Cloning of a yeast 8-oxoguanine DNA glycosylase reveals the existence of a base-excision DNA-repair protein superfamily.
Curr. Biol
6
, 968
–980
Neish
A. S.
, Anderson
S. F.
, Schlegel
B. P.
, Wei
W.
, Parvin
J. D.
(1998
) Factors associated with the mammalian RNA polymerase II holoenzyme.
Nucleic Acids Res
26
, 847
–853
Owen-Hughes
T.
, Utley
R. T.
, Côte
J.
, Peterson
C. L.
, Workman
J. L.
(1996
) Persistent site-specific remodeling of a nucleosome array by transient action of the SWI/SNF complex.
Science
273
, 513
–516
Paro
R.
, Hogness
D.S.
(1991
) The Polycomb protein shares a homologous domain with a heterochromatin-associated protein of Drosophila.
Proc. Natl. Acad. Sci. USA
88
, 263
–267
Pazin
M. J.
, Kadonaga
J. T.
(1997
) SWI2/SNF2 and related proteins: ATP-driven motors that disrupt protein-DNA interactions?.
Cell
88
, 737
–740
Peterson
A. J.
, Kyba
M.
, Bornemann
D.
, Morgan
K.
, Brock
H. W.
, Simon
J.
(1997
) A domain shared by the Polycomb group proteins Scm and ph mediates heterotypic and homotypic interactions.
Mol. Cell Biol
17
, 6683
–6692
Peterson
C. L.
(1996
) Multiple SWItches to turn on chromatin?.
Curr. Opin. Genet. Dev
6
, 171
–175
Peterson
C. L.
, Herskowitz
I.
(1992
) Characterization of the Yeast SWI1, SWI2, and SWI3 Genes Which Encode a Global Activator of Transcription.
Cell
68
, 573
–583
Peterson
C. L.
, Tamkun
J. W.
(1995
) The SWI-SNF complex: a chromatin remodeling machine?.
Trends Biochem. Sci
20
, 143
–146
Pirrotta
V.
(1997
) PcG complexes and chromatin silencing.
Curr. Opin. Genet. Dev
7
, 249
–258
Platero
J. S.
, Sharp
E. J.
, Adler
P. N.
, Eissenberg
J. C.
(1996
) In vivo assay for protein-protein interactions using Drosophila chromosomes.
Chromosoma
104
, 393
–404
Poch
O.
, Winsor
B.
(1997
) Who's who among the Saccharomyces cerevisiae actin-related proteins? A classification and nomenclature proposal for a large family.
Yeast
13
, 1053
–1058
Prelich
G.
, Winston
F.
(1993
) Mutations that suppress the deletion of an upstream activating sequence in yeast: involvement of a protein kinase and histone H3 in repressing transcription in vivo.
Genetics
135
, 665
–676
Shearn
A.
(1989
) The ash-1, ash-2 and trithorax genes of Drosophila melanogaster are functionally related.
Genetics
121
, 517
–25
Simon
J.
(1995
) Locking in stable states of gene expression: transcriptional control during Drosophila development.
Curr. Opin. Cell Biol
7
, 376
–385
Sinclair
D.
, Milne
T.
, Hodgson
J.
, Shellard
J.
, Salinas
C.
, Kyba
M.
, Randazzo
F.
, Brock
H.
(1998
) The additional sex combs gene of Drosophila encodes a chromatin protein that binds to shared and unique polycomb group sites on polytene chromosomes.
Development
125
, 1207
–1216
Strutt
H.
, Paro
R.
(1997
) The polycomb group protein complex of Drosophilamelanogaster has different compositions at different target genes.
Mol. Cell Biol
17
, 6773
–6783
Tamkun
J. W.
, Deuring
R.
, Scott
M. P.
, Kissinger
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
Treich
I.
, Cairns
B.
, De Los Santos
B.
, Brewster
E.
, Carlson
M.
(1995
) SNF11, a new component of the yeast SNF-SWI complex that interacts with a conserved region of SNF2.
Mol. Cell Biol
15
, 4240
–4248
Tripoulas
N.
, LaJeunesse
D.
, Gildea
J.
, Shearn
A.
(1996
) The Drosophila ash1 gene product, which is localized at specific sites on polytene chromosomes, contains a SET domain and a PHD finger.
Genetics
143
, 913
–928
Tsukiyama
T.
, Wu
C.
(1997
) Chromatin remodeling and transcription.
Curr. Opin. Genet. Dev
7
, 182
–91
Tsukiyama
T.
, Daniel
C.
, Tamkun
J. W.
, Wu
C.
(1995
) ISWI, a member of the SWI2/SNF2 ATPase family, encodes the 140 kDa subunit of the nucleosome remodeling factor.
Cell
83
, 1021
–1026
Wang
W.
, Chi
T.
, Xue
Y.
, Zhou
S.
, Kuo
A.
, Crabtree
G.R.
(1998
) Architectural DNA binding by a high-mobility-group/kinesin-like subunit in mammalian SWI/SNF-related complexes.
Proc. Natl Acad. Sci. USA
95
, 492
–498
Wang
W.
, Côte
J.
, Xue
Y.
, Zhou
S.
, Khavari
P. A.
, Biggar
S. R.
, Muchardt
C.
, Kalpana
G. V.
, Goff
S. P.
, Yaniv
M.
, Workman
J. L.
, Crabtree
G. R.
(1996
) Purification and biochemical heterogeneity of the mammalian SWI-SNF complex.
EMBO J
15
, 5370
–82
Wang
W.
, Xue
Y.
, Zhou
S.
, Kuo
A.
, Cairns
B. R.
, Crabtree
G. R.
(1996
) Diversity and specialization of mammalian SWI/SNF complexes.
Genes Dev
10
, 2117
–2130
Wilson
C. J.
, Chao
D. M.
, Imbalzano
A. N.
, Schnitzler
G. R.
, Kingston
R. E.
, Young
R. A.
(1996
) RNA polymerase II holoenzyme contains SWI/SNF regulators involved in chromatin remodeling.
Cell
84
, 235
–244
Zlatanova
J.
, van Holde
K.
(1998
) Binding to four-way junction DNA: a common property of architectural proteins?.
FASEB J
12
, 421
–431
This content is only available via PDF.
© 1998 by Company of Biologists
1998
