Normal apoptosis occurs continuously in the olfactory neuroepithelium of adult vertebrates, making it a useful model for studying neuronal apoptosis. Here we demonstrate that overexpression of the anti-apoptotic Bag-1 gene in olfactory neuronal cells confers a strong resistance to apoptosis. Conversely decreased levels of Bag-1 were found to precede a massive wave of olfactory neuronal apoptosis triggered by synaptic target ablation. We show that the decrease is brought about by ubiquitination and subsequent degradation of the Bag-1 protein. The ring finger protein Siah-2 is a likely candidate for the ubiquitination reaction since Siah-2 mRNA accumulated in lesioned olfactory neuroepithelium and overexpression of Siah-2 stimulated Bag-1 ubiquitination and degradation in transient expression assays. These results together identify destabilization of Bag-1 as a necessary step in olfactory neuronal apoptosis.

Bardelli
A.
,
Longati
P.
,
Albero
D.
,
Goruppi
S.
,
Schneider
C.
,
Ponzetto
C.
,
Comoglio
P. M.
(
1996
).
HGF receptor associates with the anti-apoptotic protein BAG-1 and prevents cell death.
EMBO J
15
,
6205
6212
Bradshaw
R. B.
(
1967
).
Olfactory neuroblastomas; an uncommon nasal tumour.
J. Laryngol. Otol
81
,
1177
1181
Caggiano
M.
,
Kauer
J. S.
,
Hunter
D. D.
(
1994
).
Globose basal cells are neuronal progenitors in the olfactory epithelium: a lineage analysis using a replication-incompetent retrovirus.
Neuron
13
,
339
352
Chau
V.
,
Tobias
J. W.
,
Bachmair
A.
,
Marriott
D.
,
Ecker
D. J.
,
Gonda
D. K.
,
Varshavsky
A.
(
1989
).
A multiubiquitin chain is confined to specific lysine in a targeted short-lived protein.
Science
243
,
1576
1583
Clevenger
C. V.
,
Thickman
K.
,
Ngo
W.
,
Chang
W. P.
,
Takayama
S.
,
Reed
J. C.
(
1997
).
Role of Bag-1 in the survival and proliferation of the cytokine-dependent lymphocyte lines, Ba/F3 and Nb2.
Mol. Endocrinol
11
,
608
618
Coronas
V.
,
Feron
F.
,
Hen
R.
,
Sicard
G.
,
Jourdan
F.
,
Moyse
E.
(
1997
).
In vitro induction of apoptosis or differentiation by dopamine in an immortalized olfactory neuronal cell line.
J. Neurochem
69
,
1870
1881
Della
N. G.
,
Senior
P. V.
,
Bowtell
D. D.
(
1993
).
Isolation and characterisation of murine homologues of the Drosophila seven in absentia gene (sina).
Development
117
,
1333
1343
Farbman
A. I.
,
Buchholtz
J. A.
,
Suzuki
Y.
,
Coines
A.
,
Speert
D.
(
1999
).
A molecular basis of cell death in olfactory epithelium.
J. Comp. Neurol
414
,
306
314
Franklin
R. J. M.
,
Barnett
S. C.
(
2000
).
Olfactory ensheathing cells and CNS regeneration: the sweet smell of success?.
Neuron
28
,
15
18
Freemont
P. S.
(
2000
).
RING for destruction?.
Curr. Biol
10
,
84
–.
Froesch
B. A.
,
Takayama
S.
,
Reed
J. C.
(
1998
).
BAG-1L protein enhances androgen receptor function.
J. Biol. Chem
273
,
11660
11666
Fujii
H.
,
Hamada
H.
(
1993
).
A CNS-specific POU transcription factor, Brn-2, is required for establishing mammalian neural cell lineages.
Neuron
11
,
1197
1206
Graziadei
P. P.
(
1973
).
Cell dynamics in the olfactory mucosa.
Tissue Cell
5
,
113
131
Hayashi
T.
,
Sakai
K.
,
Sasaki
C.
,
Itoyama
Y.
,
Abe
K.
(
2000
).
Loss of bag-1 immunoreactivity in rat brain after transient middle cerebral artery occlusion.
Brain Res
852
,
496
500
Hirose
T.
,
Scheithauer
B. W.
,
Lopes
M. B.
,
Gerber
H. A.
,
Altermatt
H. J.
,
Harner
S. G.
,
VandenBerg
S. R.
(
1995
).
Olfactory neuroblastoma. An immunohistochemical, ultrastructural, and flow cytometric study.
Cancer
76
,
4
19
Holcomb
J. D.
,
Mumm
J. S.
,
Calof
A. L.
(
1995
).
Apoptosis in the neuronal lineage of the mouse olfactory epithelium: regulation in vivo and in vitro.
Dev. Biol
172
,
307
323
Kastner
A.
,
Moyse
E.
,
Bauer
S.
,
Jourdan
F.
,
Brun
G.
(
2000
).
Unusual regulation of cyclin D1 and cyclin-dependent kinases cdk2 and cdk4 during in vivo mitotic stimulation of olfactory neuron progenitors in adult mouse.
J. Neurochem
74
,
2343
2349
Kullmann
M.
,
Schneikert
J.
,
Moll
J.
,
Heck
S.
,
Zeiner
M.
,
Gehring
U.
,
Cato
A. C.
(
1998
).
RAP46 is a negative regulator of glucocorticoid receptor action and hormone-induced apoptosis.
J. Biol. Chem
273
,
14620
14625
Kumar
S.
,
Talis
A. L.
,
Howley
P. M.
(
1999
).
Identification of HHR23A as a substrate for E6-associated protein-mediated ubiquitination.
J. Biol. Chem
274
,
18785
18792
Kunkel
T. A.
,
Roberts
J. D.
,
Zakour
R. A.
(
1987
).
Rapid and efficient site-specific mutagenesis without phenotypic selection.
Methods Enzymol
154
,
367
382
Li
S.
,
Li
Y.
,
Carthew
R. W.
,
Lai
Z. C.
(
1997
).
Photoreceptor cell differentiation requires regulated proteolysis of the transcriptional repressor Tramtrack.
Cell
90
,
469
478
Lorick
K. L.
,
Jensen
J. P.
,
Fang
S.
,
Ong
A. M.
,
Hatakeyama
S.
,
Weissman
A. M.
(
1999
).
RING fingers mediate ubiquitin-conjugating enzyme (E2)-dependent ubiquitination.
Proc. Natl. Acad. Sci. USA
96
,
11364
11369
Luders
J.
,
Demand
J.
,
Höhfeld
J.
(
2000
).
The ubiquitin-related BAG-1 provides a link between the molecular chaperones Hsc70/Hsp70 and the proteasome.
J. Biol. Chem
275
,
4613
4617
Mahalik
T. J.
(
1996
).
Apparent apoptotic cell death in the olfactory epithelium of adult rodents: death occurs at different developmental stages.
J. Comp. Neurol
372
,
457
464
Matsuzawa
S.
,
Takayama
S.
,
Froesch
B. A.
,
Zapata
J. M.
,
Reed
J. C.
(
1998
).
p53-inducible human homologue of Drosophila seven in absentia (Siah) inhibits cell growth: suppression by BAG-1.
EMBO J
17
,
2736
2747
Michel
D.
,
Moyse
E.
,
Brun
G.
,
Jourdan
F.
(
1994
).
Induction of apoptosis in mouse olfactory neuroepithelium by synaptic target ablation.
Neuroreport
5
,
1329
1332
Michel
D.
,
Moyse
E.
,
Trembleau
A.
,
Jourdan
F.
,
Brun
G.
(
1997
).
Clusterin/ApoJ expression is associated with neuronal apoptosis in the olfactory mucosa of the adult mouse.
J. Cell. Sci
110
,
1635
1645
Nemani
M.
,
Linares-Cruz
G.
,
Bruzzoni-Giovanelli
H.
,
Roperch
J. P.
,
Tuynder
M.
,
Bougueleret
L.
,
Cherif
D.
,
Medhioub
M.
,
Pasturaud
P.
,
Alvaro
V.
, et al. 
. (
1996
).
Activation of the human homologue of the Drosophilasina gene in apoptosis and tumor suppression.
Proc. Natl. Acad. Sci. USA
93
,
9039
9042
Packham
G.
,
Brimmell
M.
,
Cleveland
J. L.
(
1997
).
Mammalian cells express two differently localized Bag-1 isoforms generated by alternative translation initiation.
Biochem. J
328
,
807
813
Reed
J. C.
(
1999
).
Dysregulation of apoptosis in cancer.
J. Clin. Oncol
17
,
2941
2953
Rösl
F.
(
1992
).
A simple and rapid method for detection of apoptosis in human cells.
Nucl. Acids Res
20
,
5243
–.
Sadoul
R.
,
Fernandez
P. A.
,
Quiquerez
A. L.
,
Martinou
I.
,
Maki
M.
,
Schroter
M.
,
Becherer
J. D.
,
Irmler
M.
,
Tschopp
J.
,
Martinou
J. C.
(
1996
).
Involvement of the proteasome in the programmed cell death of NGF-deprived sympathetic neurons.
EMBO J
15
,
3845
3852
Sakahira
H.
,
Enari
M.
,
Nagata
S.
(
1998
).
Cleavage of CAD inhibitor in CAD activation and DNA degradation during apoptosis.
Nature
391
,
96
99
Schauber
C.
,
Chen
L.
,
Tongaonkar
P.
,
Vega
I.
,
Lambertson
D.
,
Potts
W.
,
Madura
K.
(
1998
).
Rad23 links DNA repair to the ubiquitin/proteasome pathway.
Nature
391
,
715
718
Schwartz-Levey
M.
,
Chikaraishi
D. M.
,
Kauer
J. S.
(
1991
).
Characterization of potential precursor populations in the mouse olfactory epithelium using immunocytochemistry and autoradiography.
J. Neurosci
11
,
3556
3564
Servenius
B.
,
Vernachio
J.
,
Price
J.
,
Andersson
L. C.
,
Peterson
P. A.
(
1994
).
Metastasizing neuroblastomas in mice transgenic for simian virus 40 large T (SV40T) under the olfactory marker protein gene promoter.
Cancer Res
54
,
5198
5205
Takayama
S.
,
Sato
T.
,
Krajewski
S.
,
Kochel
K.
,
Irie
S.
,
Millan
J.A.
,
Reed
J. C.
(
1995
).
Cloning and functional analysis of BAG-1: a novel Bcl-2-binding protein with anti-cell death activity.
Cell
80
,
279
284
Wang
H. G.
,
Takayama
S.
,
Rapp
U. R.
,
Reed
J. C.
(
1996
).
Bcl-2 interacting protein, BAG-1, binds to and activates the kinase Raf-1.
Proc. Natl. Acad. Sci. USA
93
,
7063
7068
Yang
X.
,
Chernenko
G.
,
Hao
Y.
,
Ding
Z.
,
Pater
M. M.
,
Pater
A.
,
Tang
S. C.
(
1998
).
Human BAG-1/RAP46 protein is generated as four isoforms by alternative translation initiation and overexpressed in cancer cells.
Oncogene
17
,
981
989
Yang
X.
,
Pater
A.
,
Tang
S. C.
(
1999
).
Cloning and characterization of the human BAG-1 gene promoter: upregulation by tumor-derived p53 mutants.
Oncogene
18
,
4546
4553
Yang
Y.
,
Fang
S.
,
Jensen
J. P.
,
Weissman
A. M.
,
Ashwell
J. D.
(
2000
).
Ubiquitin protein ligase activity of IAPs and their degradation in proteasomes in response to apoptotic stimuli.
Science
288
,
874
877
Zeiner
M.
,
Gebauer
M.
,
Gehring
U.
(
1997
).
Mammalian protein RAP46: an interaction partner and modulator of 70 kDa heat shock proteins.
EMBO J
16
,
5483
5490
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