XIPOU 2, a member of the class III POU domain family, is expressed initially in Spemann's organizer, and later, in discrete regions of the developing nervous system in Xenopus laevis. XIPOU 2 may act downstream from initial neural induction events, since it is activated by the neural inducer, noggin. To determine if XIPOU 2 participates in the early events of neurogenesis, synthetic mRNA was microinjected into specific blastomeres of the 32-cell stage embryo. Misexpression of XIPOU 2 in the epidermis causes a direct switch in cell fate from an epidermal to a neuronal phenotype. In the absence of mesoderm induction, XIPOU 2 has the ability to induce a neuronal phenotype in uncommitted ectoderm. These data demonstrate the potential of XIPOU 2 to act as a master regulator of neurogenesis.

Reference

Reference
Agarwal
V. R.
,
Sato
S. M.
(
1991
)
XlPOU 1 and XlPOU 2, two novel POU domain genes expressed in the dorsoanterior region of Xenopus embryos.
Dev. Biol
147
,
363
373
Bhat
K. M.
,
Schedl
P.
(
1994
)
The Drosophila miti-mere gene, a member of the POU family is required for the specification of the RP2/sibling lineage during neurogenesis.
Development
120
,
1483
1501
Blumberg
B.
,
Wright
C. V. E.
,
De Robertis
E. M.
,
Cho
K. W. Y.
(
1991
)
Organizer-specific homeobox genes in Xenopus laevis embryos.
Science
253
,
194
196
Cabrera
C. V.
(
1992
)
The generation of cell diversity during early neruogenesis in Drosophila.
Development
115
,
893
901
Campos-Ortega
J. A.
(
1990
)
Mechanisms of a cellular decision during embryonic development of Drosophila melanogaster epidermogenesis or neurogenesis.
Adv. Genet
27
,
403
453
Campuzano
S.
,
Modolell
J.
(
1992
)
Patterning of the Drosophila nervous system: the achaete-scute gene complex.
Trends Genet
6
,
202
208
Coffman
C. R.
,
Skoglund
P.
,
Harris
W. A.
,
Kintner
C. R.
(
1993
)
Expression of an extracellular deletion of Xotch diverts cell fate in Xenopus embryos.
Cell
73
,
659
671
Dale
L.
,
Slack
J. M. W.
(
1987
)
Fate map for the 32-cell stage of Xenopus laevis.
Development
99
,
527
551
Dassow
G.
,
von, Schmidt
J. E.
,
Kimelman
D.
(
1993
)
Induction of the Xenopus organizer: expression and regulation of Xnot, a novel FGF and activin-regulated homeo box gene.
Genes Dev
7
,
355
366
Dawid
I. B.
(
1994
)
Intracellular signaling and gene regulation during early embryogenesis of Xenopus laevis.
J. Biol. Chem
269
,
6259
6262
Detrick
R. J.
,
Dickey
D.
,
Kintner
C. R.
(
1990
)
The effects of N-cadherin misexpression on morphogenesis in Xenopus embryos.
Neuron
4
,
493
506
Dirksen
M. L.
,
Jamrich
M.
(
1992
)
A novel, activin-inducible, blastopore lip-specific gene of Xenopus laevis contains a fork head DNA-binding domain.
Genes Dev
6
,
599
608
Dixon
J. E.
,
Kintner
C. R.
(
1989
)
Cellular contacts required for neural induction in Xenopus embryos: evidence for two signals.
Development
106
,
749
757
Doniach
T.
,
Phillips
C. R.
,
Gerhart
J. C.
(
1992
)
Planar induction of anteroposterior pattern in the developing central nervous system of Xenopus laevis.
Science
257
,
542
545
Evan
G. I.
,
Lewis
G. K.
,
Ramsay
G.
,
Bishop
J. M.
(
1985
)
Isolation of a monoclonal antibody specific for human c-myc proto-oncogene product.
Mol. Cell. Biol
5
,
3610
3616
Feinberg
A. P.
,
Vogelstein
B.
(
1984
)
A technique for radiolabeling DNA fragments separated by gel electrophoresis.
Analyt. Biochem
137
,
266
267
Ferreiro
B.
,
Skoglund
P.
,
Bailey
A.
,
Dorsky
R.
,
Harris
W.
(
1992
)
XASH1, a Xenopus homolog of acaete-scute a proneural gene in anterior regions of the vertebrate CNS.
Mech. Dev
40
,
25
36
Finney
M.
,
Ruvkun
G.
(
1990
)
The unc-86 gene product couples cell lineage and cell identity in C. elegans.
Cell
63
,
895
905
Fujii
H.
,
Hamada
H.
(
1994
)
A CNS-specific POU transcription factor, Br-2, is required for establishing mammalian cell lineages.
Neuron
11
,
1197
1206
Green
J. B. A.
(
1994
)
Roads to neuralness: embryonic neural induction as derepression of a default state.
Cell
77
,
317
320
Guillemot
F.
,
Lo
L. C.
,
Johnson
J. E.
,
Auerbach
A.
,
Anderson
D. J.
,
Joyner
A. L.
(
1993
)
Mammalian achaete-scute homolog 1 is required for the early development of olfactory and autonomic neurons.
Cell
75
,
463
476
Hara
Y.
,
Rovescalli
A. C.
,
Kim
Y.
,
Nirenberg
M.
(
1992
)
Structure and evolution of four POU genes expressed in mouse brain.
Proc. Natl. Acad. Sci. USA
89
,
3280
3284
Harland
R. M.
(
1991
)
In situ hybridization: An improved whole-mount method for Xenopus embryos.
Methods in Cell Biology
36
,
685
695
He
X.
,
Treacy
M. N.
,
Simmons
D. M.
,
Ingraham
H. A.
,
Swanson
L. W.
,
Rosenfeld
M. G.
(
1989
)
Expression of a large family of POU-domain regulatory genes in mammalian brain development.
Nature
340
,
35
42
Hemmati-Brivanlou
A.
,
de la Torre
J. R.
,
Holt
C.
,
Harland
R. M.
(
1991
)
Cephalic expression and molecular characterization of Xenopus En-2.
Development
111
,
715
724
Hemmati-Brivanlou
A.
,
Melton
D. A.
(
1994
)
Inhibition of activin receptor signaling promotes neuralization in Xenopus.
Cell
77
,
273
281
Hemmati-Brivanlou
A.
,
Kelly
O. G.
,
Melton
D. A.
(
1994
)
Follistatin, an antagonist of activin is expressed in the Spemann organizer and displays direct neuralizing activity.
Cell
77
,
283
295
Jan
L. Y.
,
Jan
Y. N.
(
1992
)
Neuronal specification.
Curr. Opin. Genet. Dev
2
,
608
613
Johnson
J. E.
,
Birren
S. J.
,
Anderson
D. J.
(
1990
)
Two rat homologues of Drosophila achaete-scute specifically expressed in neuronal precursors.
Nature
346
,
858
861
Kintner
C. R.
,
Melton
D. A.
(
1987
)
Expression of Xenopus N-CAM RNA in ectoderm is an early response to neural induction.
Development
99
,
311
325
Kintner
C.
(
1992
)
Molecular bases of early neural development in Xenopus embryos.
A. Rev. Neurosci
15
,
251
284
Krieg
P. A.
,
Melton
D. A.
(
1984
)
Functional. messenger RNAs are produced by SP6 in vitro transcription of cloned cDNAs.
Nucl. Acids. Res
12
,
7057
7070
Lamb
T. M.
,
Knecht
A. K.
,
Smith
W. C.
,
Stachel
S. E.
,
Economides
A. N.
,
Stahl
N.
,
Yancopolous
G. D.
,
Harland
R. M.
(
1993
)
Neural induction by the secreted polypeptide noggin.
Science
262
,
713
718
Le. Moine
C.
,
Young
W. S.
III
(
1992
)
RHS2, a new POU domain-containing gene, and its expression in the developing and adult rat.
Proc. Natl. Acad. Sci. USA
89
,
3285
3289
Mathis
J. M.
,
Simmons
D. M.
,
He
X.
,
Swanson
L. W.
,
Rosenfeld
M. G.
(
1992
)
Brain 4: a novel mammalian POU domain transcription factor exhibiting restricted brain-specific expression.
EMBOJ
11
,
2551
2561
Monuki
E. S.
,
Kuhn
R.
,
Weinmaster
G.
,
Trapp
B. D.
,
Lemke
G.
(
1990
)
Expression and activity of the POU domain transcription factor SCIP.
Science
249
,
1300
1303
Newport
J.
,
Kirschner
M.
(
1982
)
A major developmental transition in early Xenopus embryos II. Control of the onset of transcription.
Cell
30
,
687
696
Rao
Y.
(
1994
)
Conversion of a mesodermalizing molecule, the Xenopus Brachyury gene, into a neuralizing factor.
Genes Dev
8
,
939
947
Rosenfeld
M. G.
(
1991
)
POU-domain transcriptional factors: pou-er-ful developmental regulators.
Genes Dev
5
,
897
907
Ruiz i Altaba
A.
(
1990
)
Neural expression of the Xenopus homeobox gene Xhox3: evidence for a patterning neural signal that spreads through the ectoderm.
Development
108
,
595
604
Ruiz i Altaba
A.
(
1994
)
Pattern formation in the vertebrate neural plate.
Trends Neurosci
17
,
233
243
Ruiz i Altaba
A.
,
Jessell
T. M.
(
1992
)
Pintallavis, a gene expressed in the organizer and midline cells of frog embryos: involvment in the development of the neural axis.
Development
116
,
81
93
Ruvkun
G.
,
Finney
M.
(
1991
)
Regulation of transcription and cell identity by POU domain proteins.
Cell
64
,
475
478
Sargent
T. D.
,
Jamrich
M.
,
Dawid
I. B.
(
1986
)
Cell interactions and thecontrol of gene activity during early development of Xenopus laevis.
Dev. Biol
114
,
238
246
Schöler
H. R.
,
Hatzopoulos
A. K.
,
Balling
R.
,
Suzuki
N.
,
Gruss
P.
(
1989
)
A family of octamer-specific proteins present during mouse embryogenesis: evidence for germline-specific expression of an Oct-factor.
EMBO J
8
,
2543
2550
Schöler
H. R.
(
1991
)
Octamania: the POU factors in murine development.
Trends Genet
7
,
323
9
Smith
J. C.
,
Price
B. M. J.
,
Green
J. B. A.
,
Weigel
D.
,
Herrmann
B. G.
(
1991
)
Expression of a Xenopus homolog of Brachyury (T) is an immediate-early response to mesoderm induction.
Cell
67
,
70
87
Taira
M.
,
Jamrich
M.
,
Good
P. J.
,
Dawid
I. B.
(
1992
)
The LIM domain-containing homeo box gene Xlim-1 is expressed specifically in the organizer region of Xenopus gastrula embryos.
Genes Dev
6
,
356
366
Turner
D. L.
,
Weintraub
H.
(
1994
)
Expression of achaete-scutehomolog 3 in Xenopus embryos converts ectodermal cells to a neural fate.
Genes Dev
8
,
1434
1447
Verrijzer
C. P.
,
Van der Vliet
P. C.
(
1993
)
POU domain transcription factors.
Biochim. Biophys. Acta
1173
,
1
21
Wright
C. V. E.
,
Morita
E. A.
,
Wilkin
D. J.
,
De Robertis
E. M.
(
1990
)
The Xenopus XlHbox 6 homeo protein, a marker of posterior neural induction, is expressed in proliferating neurons.
Development
109
,
225
234
Yang
X.
,
Yeo
S.
,
Dick
T.
,
Chia
W.
(
1993
)
The role of a Drosophila POU homeodomain gene in the specification of neural precursor cell identity in the developing central nervous system.
Genes Dev
7
,
504
516
Zimmerman
K.
,
Shih
J.
,
Bars
J.
,
Collazo
A.
,
Anderson
D. J.
(
1993
)
Xash-3, a novel Xenopus acaete-scute homolog, provides an early marker of planar neural induction and position along the mediolateral axis of the neural plate.
Development
119
,
221
232
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