The cellular transcription factor E2F plays a critical role in integrating cell cycle progression with the transcription apparatus by virtue of a physical interaction and control by key regulators of the cell cycle, such as pRb, cyclins and cyclin-dependent kinases. Generic E2F DNA binding activity arises when a member of two families of proteins, E2F and DP, form heterodimeric complexes, an interaction which results in co-operative transcriptional and DNA binding activity. Here, we characterise a new and hitherto unexpected mechanism of control influencing the activity of E2F which is mediated at the level of intracellular location through a dependence on heterodimer formation for nuclear translocation. Nuclear accumulation is dramatically influenced by two distinct processes: alternative splicing of a nuclear localization signal and subunit composition of the E2F heterodimer. These data define a new level of control in the E2F transcription factor whereby interplay between subunits dictates the levels of nuclear DNA binding activity.

Bandara
L. R.
,
La Thangue
N. B.
(
1991
).
Adenovirus Ela prevents the retinoblastoma gene product from complexing with a cellular transcription factor.
Nature
351
,
494
497
Bandara
L. R.
,
Adamczewski
J. P.
,
Hunt
T.
,
La Thangue
N. B.
(
1991
).
Cyclin A and the retinoblastoma gene product complex with a common transcription factor.
Nature
352
,
249
251
Bandara
L. R.
,
Buck
V. M.
,
Zamanian
M.
,
Johnston
L. H.
,
La Thangue
N. B.
(
1993
).
Functional synergy between DP-1 and E2F-1 in the cell cycle-regulating transcription factor DRTF1/E2F.
EMBO J
13
,
4317
4324
Bandara
L. R.
,
Lam
E. W.-F.
,
Sorensen
T. S.
,
Zamanian
M.
,
Girling
R.
,
La Thangue
N. B.
(
1994
).
DP-1: a cell cycle-regulated and phosphorylated component of transcription factor DRTF1/E2F which is functionally important for recognition by pRb and the adenovirus E4 orf 6/7 protein.
EMBO J
13
,
3104
3114
Beijersbergen
R. L.
,
Kerkhoven
R. M.
,
Zhu
L.
,
Carlee
L.
,
Voorhoeve
P. M.
,
Bernards
R.
(
1994
).
E2F-4, a new member of the E2F gene family, has oncogenic activity and associates with p107 in vivo.
Genes Dev
8
,
2680
2690
Beijersbergen
R. L.
,
Carlee
L.
,
Kerkhoven
R. M.
,
Bernards
R.
(
1995
).
Regulation of the retinoblastoma protein-related p107 by G1cyclin complexes.
Genes Dev
9
,
1340
1353
Bentolila
L. A.
,
d'Andon
M. F.
,
Nguyen
Q. T.
,
Martinez
O.
,
Rougeon
F.
,
Doyen
N.
(
1995
).
The two isoforms of mouse terminal deoxynucleotidyl transferase differ in both the ability to add N regions and subcellular localization.
EMBO J
14
,
4221
4229
Boulikas
T.
(
1993
).
Nuclear localization signals (NLS).
Crit. Rev. Euk. Gene Exp
3
,
193
227
Boulikas
T.
(
1994
).
Putative nuclear localization signals (NLS) in protein transcription factors.
J. Cell. Biochem
55
,
32
38
Buck
V.
,
Allen
K. E.
,
Sorensen
T.
,
Bybee
A.
,
Hijmans
E. M.
,
Voorhoeve
P. M.
,
Bernards
R.
,
La Thangue
N. B.
(
1995
).
Molecular and functional characterisation of E2F-5, a new member of the E2F family.
Oncogene
11
,
31
38
Chang
J.
,
Lee
K. J.
,
Jang
K. L.
,
Lee
E. K.
,
Baek
G. H.
,
Sung
Y. C.
(
1995
).
Human foamy virus Bel1 transactivator contains a bipartite nuclear localization determinant which is sensitive to protein context and triple multimerization domains.
J. Virol
69
,
801
808
Chellappan
S. P.
,
Hiebert
S.
,
Mudryj
M.
,
Horowitz
J. M.
,
Nevins
J. R.
(
1991
).
The E2F transcription factor is a cellular target for the Rb protein.
Cell
65
,
1053
1061
Chellappan
S.
,
Kraus
V. B.
,
Kroger
Bu.
,
Munger
K.
,
Howley
M.
,
Phelps
W. C.
,
Nevins
J. R.
(
1992
).
Adenovirus E1A, simian virua 40 tumor antigen, and human papillomavirus E7 protein share the capacity to disrupt the interaction between transcription factor E2F and the retinoblastoma gene product.
Proc. Nat. Acad. Sci. USA
89
,
4549
4553
Dingwall
C.
,
Laskey
R.
(
1991
).
Nuclear targeting sequences- a common consensus?.
Trends Biochem. Sci
16
,
478
481
Dowdy
S. F.
,
Hinds
P. W.
,
Louie
K.
,
Reed
S. I.
,
Arnold
A.
,
Weinberg
R. A.
(
1993
).
Physical interaction of the retinoblastoma protein with human cyclins.
Cell
73
,
499
511
Evans
R. M.
(
1988
).
The steroid and thyroid hormone receptor superfamily.
Science
240
,
889
895
Ewen
M. E.
,
Sluss
H. K.
,
Sherr
C. J.
,
Matsushime
H.
,
Kato
J. Y.
,
Livingston
D. M.
(
1993
).
Functional interactions of the retinoblastoma protein with mammalian D-type cyclins.
Cell
73
,
487
497
Fabre
E.
,
Hurt
E. C.
(
1994
).
Nuclear transport.
Curr. Opin. Cell Biol
6
,
335
342
Flemington
E. K.
,
Speck
S. H.
,
Kaelin
W. G.
(
1993
).
Mediated transactivation is inhibited by complex formation with the retinoblastoma susceptibility gene product.
Proc. Nat. Acad. Sci. USA
90
,
6914
6918
Ginsberg
D.
,
Vairo
G.
,
Chittendon
T.
,
Xiao
Z.-X.
,
Xu
G.
,
Wydner
K. K.
,
De Caprio
J. A.
,
Lawrence
J. B.
,
Livingston
D. M.
(
1994
).
E2F-4, a new E2F transcription factor family member, interacts with p107 and has transforming potential.
Genes Dev
8
,
2939
2952
Girling
R.
,
Partridge
J. F.
,
Bandara
L. R.
,
Burden
N.
,
Totty
N. F.
,
Hsuan
J. J.
,
La Thangue
N. B.
(
1993
).
A new component of the transcription factor DRTF1/E2F.
Nature
362
,
83
87
Girling
R.
,
Bandara
L. R.
,
Ormondroyd
E.
,
Lam
E. W.-F.
,
Kotecha
S.
,
Mohun
T.
,
La Thangue
N. B.
(
1994
).
Molecular characterisation of Xenopus laevis DP proteins.
Mol. Biol. Cell
5
,
1081
1092
Helin
K.
,
Lees
J. A.
,
Vidal
M.
,
Dyson
N.
,
Harlow
E.
,
Fattaey
A.
(
1992
).
A cDNA encoding a pRb-binding protein with properties of the transcription factor E2F.
Cell
70
,
337
350
Helin
K.
,
Harlow
E.
,
Fattaey
A. R.
(
1993
).
Inhibition of E2F-1 trans-activation by direct binding of the retinoblastoma protein.
Mol. Cell. Biol
13
,
6501
6508
Helin
K.
,
Wu
C.-L.
,
Fattaey
A. R.
,
Lees
J. A.
,
Dynlacht
B. D.
,
Ngwu
C.
,
Harlow
E.
(
1993
).
Heterodimerization of the transcription factors E2F-1 and DP-1 leads to cooperative trans-activation.
Genes Dev
7
,
1850
1861
Hiebert
S. W.
,
Chellappan
S. P.
,
Horowitz
J. M.
,
Nevins
J. R.
(
1992
).
The interaction of Rb with E2F coincides with an inhibition of the transcriptional activity of E2F.
Genes Dev
6
,
177
185
Hijmans
E. M.
,
Voorhoeve
P. M.
,
Beijersbergen
R. L.
,
Veer
L. J.
,
van't Bernards
R.
(
1995
).
E2F-5, a new E2F family member that interacts with p130 i n vivo.
Mol. Cell. Biol
15
,
3082
3089
Hinds
P. W.
,
Mittnacht
S.
,
Dulic
V.
,
Arnold
A.
,
Reed
S. I.
,
Weinberg
R. A.
(
1992
).
Regulation of retinoblastoma protein functions by ectopic expression of human cyclins.
Cell
70
,
993
1006
Ivey-Hoyle
M.
,
Conroy
R.
,
Huber
H. E.
,
Goodhart
P. J.
,
Oliff
A.
,
Heimbrook
D. C.
(
1993
).
Cloning and characterization of E2F-2, a novel protein with the biochemical properties of transcription factor E2F.
Mol. Cell. Biol
13
,
7802
7812
Johnson
D. G.
,
Cress
W. D.
,
Jakoi
L.
,
Nevins
J. R.
(
1994
).
Oncogenic capacity of the E2F-1 gene.
Proc. Nat. Acad. Sci. USA
91
,
12823
12827
Jooss
K.
,
Lam
E. W.-F.
,
Bybee
A.
,
Girling
R.
,
Muller
R.
,
La Thangue
N. B.
(
1995
).
Proto-oncogenic properties of the DP family of proteins.
Oncogene
10
,
1529
1536
Kaelin
W. G.
,
Krek
W.
,
Sellers
W. R.
,
De Caprio
J. A.
,
Ajchanbaum
F.
,
Fuchs
C. S.
,
Chittenden
T.
,
Li.
Y.
,
Farnham
P. J.
,
Blanar
M. A.
,
Livingston
D. M.
,
Flemington
E. K.
(
1992
).
Expression cloning of a cDNA encoding a retinoblastoma-binding protein with E2F-like properties.
Cell
70
,
351
364
Krek
W.
,
Livingston
D. M.
,
Shirodkar
S.
(
1993
).
Binding to DNA and the retinoblastoma gene product promoted by complex formation of different E2F family members.
Science
262
,
1557
1560
Krek
W.
,
Ewen
M. E.
,
Shirodkar
S.
,
Arany
Z.
,
Kaelin
W. G.
,
Livingston
D. M.
(
1994
).
Negative regulation of the growth-promoting transcription factor E2F-1 by a stably bound cyclin A-dependent protein kinase.
Cell
78
,
161
172
Krek
W.
,
Xu
G.
,
Livingston
D. M.
(
1995
).
Cyclin A-kinase regulation of E2F-1 DNA binding function underlies suppression of an S phase checkpoint.
Cell
83
,
1149
1158
La Casse
E. C.
,
Lefebvre
Y. A.
(
1995
).
Nuclear localization signals overlap DNA-or RNA binding domains in nucleic acid binding proteins.
Nucl. Acids Res
23
,
1647
1656
La Thangue
N. B.
(
1994
).
DRTF1/E2F: an expanding family of heterodimeric transcription factors implicated in cell-cycle control.
Trends Biochem. Sci
19
,
108
114
Lees
E.
,
Faha
B.
,
Dulic
V.
,
Reed
S. I.
,
Harlow
E.
(
1992
).
Cyclin E/cdk2 and cyclin A/cdk2 kinases associate with p107 and E2F in a temporally distinct matter.
Genes Dev
6
,
1874
1885
Lees
J. A.
,
Saito
M.
,
Vidal
M.
,
Valentine
M.
,
Look
T.
,
Harlow
E.
,
Dyson
N.
,
Helin
K.
(
1993
).
The retinoblastoma protein binds to a family of E2F transcription factors.
Mol. Cell. Biol
13
,
7813
7825
Makela
T. P.
,
Koskinen
P. J.
,
Vastrik
L.
,
Alitalo
K.
(
1992
).
Alternative forms of Max as enhancers or suppressors of Myc-ras co-transformation.
Science
256
,
373
377
Martin
K.
,
Trouche
D.
,
Hagemeier
C.
,
Sørensen
T. S.
,
La Thangue
N. B.
,
Kouzarides
T.
(
1995
).
Stimulation of E2F/DP1 transcriptional activity by MDM2 oncoprotein.
Nature
375
,
691
694
Melchior
F.
,
Gerace
L.
(
1995
).
Mechanisms of nuclear protein import.
Curr. Opin. Cell Biol
7
,
310
318
Mittnacht
S.
,
Weinberg
R. A.
(
1991
).
G1/S phosphorylation of the retinoblastoma protein is associated with an altered affinity for the nuclear compartment.
Cell
65
,
381
393
Morris
J. D.
,
Crook
T.
,
Bandara
L. R.
,
Davies
R.
,
La Thangue
N. B.
,
Vousden
K. H.
(
1993
).
Human papillomavirus type 16 E7 regulates E2F and contributes to mitogenic signalling.
Oncogene
8
,
893
898
Muller
R.
(
1995
).
Transcriptional regulation during the mammalian cell cycle.
Trends Genet
11
,
173
178
Nevins
J. R.
(
1992
).
E2F: a link between the Rb tumor suppressor protein and viral oncoproteins.
Science
258
,
424
429
Ormondroyd
E.
,
de la Luna
S.
,
La Thangue
N. B.
(
1995
).
A new member of the DP family, DP-3, with distinct protein products suggests a regulatory role for alternative splicing in the cell cycle transcription factor DRTF1/E2F.
Oncogene
11
,
1437
1446
Robbins
J.
,
Dilworth
S. M.
,
Laskey
R. A.
,
Dingwall
C.
(
1991
).
Two interdependent basic domains in nucleoplasmin nuclear targeting sequence: identification of a class of bipartite nuclear targeting sequence.
Cell
64
,
615
623
Sardet
C.
,
Vidal
M.
,
Cobrinik
D.
,
Geng
Y.
,
Onufryk
C.
,
Chen
A.
,
Weinberg
R. A.
(
1995
).
E2F-4 and E2F-5, two members of the E2F family, are expressed in the early phases of the cell cycle.
Proc. Nat. Acad. Sci. USA
92
,
2403
2407
Schwarz
J. K.
,
Devoto
S. H.
,
Smith
E. J.
,
Chellappan
S. P.
,
Jakoi
L.
,
Nevins
J. R.
(
1993
).
Interactions of the p107 and Rb proteins with E2F during the cell proliferation response.
EMBO J
12
,
1013
1020
Shan
B.
,
Zhu
X.
,
Chen
P.-L.
,
Durfee
T.
,
Yang
Y.
,
Sharp
D.
,
Lee
W. H.
(
1992
).
Molecular cloning of cellular genes encoding retinoblastoma-associated proteins: Identification of a gene with properties of the transcription factor E2F.
Mol. CellBiol
12
,
5620
5631
Sherr
C. J.
(
1993
).
Mammalian G1 cyclins.
Cell
73
,
1059
1065
Slansky
J. E.
,
Li
Y.
,
Kaelin
W. G.
,
Farnham
P. J.
(
1993
).
A protein synthesis-dependent increase in E2F1 mRNA correlates with growth regulation of the dihydrofolate reductase promoter.
Mol. Cell Biol
13
,
1610
1618
Srinivasan
M.
,
Edman
C. F.
,
Schulman
H.
(
1994
).
Alternative splicingintroduces a nuclear localization signal that targets multifunctional CaM kinase to the nucleus.
J. CellBiol
126
,
839
852
Tang
T. K.
,
Tang
C. C.
,
Chao
Y. J.
,
Wu
C.
(
1994
).
Nuclear mitotic apparatus protein (NuMA): spindle association, nuclear targeting and differential subcellular localization of various NuMA isoforms.
J. Cell Sci
107
,
1389
1402
Vairo
G.
,
Livingston
D. M.
,
Ginsberg
D.
(
1995
).
Functional interaction between E2F-4 and p130: evidence for distinct mechanisms underlying growth suppression by different retinoblastoma protein family members.
Genes Dev
9
,
869
881
Vandromme
M.
,
Gauthierrouviere
C.
,
Lamb
N.
,
Fernandez
A.
(
1996
).
Regulation of transcription factor localization- fine tuning of gene-expression.
Trends Biochem. Sci
21
,
59
64
Webster
N. J. G.
,
Green
S.
,
Tasset
D.
,
Ponglikitmongkol
M.
,
Chambon
P.
(
1989
).
The transcriptional activation function located in the hormone binding domain of the human estrogen receptor is not encoded in a single exon.
EMBO. J
8
,
1441
1446
Weinberg
R. A.
(
1995
).
The retinoblastoma protein and cell cycle control.
Cell
81
,
323
330
Whiteside
S. T.
,
Goodbourn
S.
(
1993
).
Signal transduction and nuclear targeting: regulation of transcription factor activity by subcellular localisation.
J. Cell Sci
104
,
949
955
Wolf
D. A.
,
Hermeking
H.
,
Albert
T.
,
Herzinger
T.
,
Kind
P.
,
Eick
D.
(
1995
).
A complex between E2F and the pRb-related protein p130 is specifically targeted by the simian virus 40 large T antigen during cell transformation.
Oncogene
10
,
2067
2078
Wu
C. L.
,
Zukerberg
L. R.
,
Ngwu
C.
,
Harlow
E.
,
Lees
J. A.
(
1995
).
In vivo association of E2F and DP family proteins.
Mol. Cell Biol
15
,
2536
2546
Zamanian
M.
,
La Thangue
N. B.
(
1992
).
Adenovirus E1A prevents the retinoblastoma gene product from repressing the activity of a cellular transcription factor.
EMBO J
11
,
2603
2610
Zamanian
M.
,
La Thangue
N. B.
(
1993
).
Transcriptional repression by the Rb-related protein p107.
Mol. Biol. Cell
4
,
389
396
Zhang
Y.
,
Chellappan
S. P.
(
1995
).
Cloning and characterisation of human DP-2, a novel dimerization partner of E2F.
Oncogene
10
,
2085
2093
Zhu
L.
,
Van den Heuvel
S.
,
Helin
K.
,
Fattaey
A.
,
Ewen
M.
,
Livingston
D.
,
Dyson
N.
,
Harlow
E.
(
1993
).
Inhibition of cell proliferation by p107, a relative of the retinoblastoma protein.
Genes Dev
7
,
1111
1125
Zhu
L.
,
Enders
G.
,
Lees
J. A.
,
Beijersbergen
R. L.
,
Bernards
R.
,
Harlow
E.
(
1995
).
The pRb-related protein p107 contains two growth suppression domains: independent interactions with E2F and cyclin/cdk complexes.
EMBO J
14
,
1904
1913
Zhu
L.
,
Harlow
E.
,
Dynlacht
B. D.
(
1995
).
p107 uses a p21CIP1-related domain to bind cyclin/cdk2 and regulate interactions with E2F.
Genes Dev
9
,
1740
1752
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