A single line of epidermal seam cells lies along each side of the nematode C. elegans. During normal development, one of these cells, V5, produces a neuroblast that will give rise to a sensory structure, the postdeirid. If seam cells located either anterior or posterior to V5 are ablated however, this neuroblast formation is blocked. Because of this requirement for the presence of adjacent seam cells, we have asked whether V5's ability to produce a neuroblast depends on direct contact with its seam cell neighbors. We find that direct contact between seam cells is required for commitment to neuroblast production. Seam cells lose and reform their contacts with each other as they go through rounds of cell division during larval development. Signaling required for neuroblast formation occurs when the seam cells make contact after their first round of division. If this contact is prevented, no neuroblast is made; when it is delayed, the time of signaling is also delayed. The characteristics of these signals suggest that a seam cell must be part of a continuous epithelium in order to develop normally and that signaling may occur via a cell recognition/cell adhesion pathway. The effect of seam cell ablations on neuroblast formation is altered in mab-5(−) animals, suggesting that this HOM-C gene is part of the pathway by which seam cell signaling controls the decision to make a postdeirid neuroblast.

Aroian
R. V.
,
Koga
M.
,
Mendel
J. E.
,
Ohshima
Y.
,
Sternberg
P. W.
(
1990
)
The let-23 gene necessary for Caenorhabditis elegans vulval induction encodes a tyrosine kinase of the EGF receptor subfamily.
Nature
348
,
693
9
Aroian
R. V.
,
Sternberg
P. W.
(
1991
)
Multiple functions of let-23, a Caenorhabditis elegans receptor tyrosine kinase gene required for vulval induction.
Genetics
128
,
251
67
Austin
J.
,
Kimble
J.
(
1987
)
glp-1 is required in the germ line for regulation of the decision between mitosis and meiosis in C. elegans.
Cell
51
,
589
99
Brenner
S.
(
1974
)
The genetics of C. elegans.
Genetics
77
,
71
94
Burglin
T. R.
,
Ruvkun
G.
,
Coulson
A.
,
Hawkins
N. C.
,
McGhee
J. D.
,
Schaller
D.
,
Wittman
C.
,
Muller
F.
,
Waterston
R. H.
(
1991
)
Nematode homeobox cluster.
Nature
351
,
703
–.
Chisholm
A.
(
1991
)
Control of cell fate in the tail region of C. elegans by the gene egl-5.
Development
111
,
921
932
Clark
D. V.
,
Rogalski
T. M.
,
Donati
L. M.
,
Baillie
D. L.
(
1988
)
The unc-22 (IV) region of Caenorhabditis elegans: genetic analysis of lethal mutations.
Genetics
119
,
345
53
Clark
S. G.
,
Chisholm
A. D.
,
Horvitz
H. R.
(
1993
)
Control of cell fates in the central body region of C. elegans by the homeobox gene lin-39.
Cell
74
,
43
56
Costa
M.
,
Weir
M.
,
Coulson
A.
,
Sulston
J.
,
Kenyon
C.
(
1988
)
Posterior pattern formation in C. elegans involves position-specific expression of a gene containing a homeobox.
Cell
55
,
747
56
Cowing
D.
,
Kenyon
C.
(
1992
)
Expression of the homeotic gene mab-5 during Caenorhabditis elegans embryogenesis.
Development
116
,
481
490
Detrick
R. J.
,
Dickey
D.
,
Kintner
C. R.
(
1990
)
The effects of N-cadherin misexpression on morphogenesis in Xenopus embryos.
Neuron
4
,
493
506
Fehon
R. G.
,
Kooh
P. J.
,
Rebay
I.
,
Regan
C. L.
,
Xu
T.
,
Muskavitch
M. A.
,
Artavanis-Tsakonas
S.
(
1990
)
Molecular interactions between the protein products of the neurogenic loci Notch and Delta, two EGF-homologous genes in Drosophila.
Cell
61
,
523
34
Ferguson
E.
,
Horvitz
H.
(
1985
)
Identification and characterization of 22 genes that affect the vulval cell lineages of the nematode C. elegans.
Genetics
110
,
17
72
Francis
R.
,
Waterston
R. H.
(
1991
)
Muscle cell attachment in Caenorhabditis elegans.
J. Cell Biol
114
,
465
79
Fujimori
T.
,
Miyatani
S. a. T., M.
(
1990
)
Ectopic expression of N-cadherin perturbs histogenesis in Xenopus embryos.
Development
110
,
97
104
Greenwald
I.
,
Sternberg
P.
,
Horvitz
H.
(
1983
)
The lin-12 locus specifies cell fates in C. elegans.
Cell
34
,
435
444
Han
M.
,
Aroian
R. V.
,
Sternberg
P. W.
(
1990
)
The let-60 locus controls the switch between vulval and nonvulval cell fates in Caenorhabditis elegans.
Genetics
126
,
899
913
Han
M.
,
Sternberg
P. W.
(
1990
)
let-60, a gene that specifies cell fates during C. elegans vulval induction, encodes a ras protein.
Cell
63
,
921
31
Hill
R. J.
,
Sternberg
P. W.
(
1992
)
The gene lin-3 encodes an inductive signal for vulval development in C. elegans.
Nature
358
,
470
476
Hodgkin
J.
,
Horvitz
H. R.
,
Brenner
S.
(
1979
)
Nondisjunction mutants of the nematode Caenorhabditis elegans.
Genetics
91
,
67
94
Horvitz
H.
,
Sternberg
P.
,
Greenwald
I.
,
Fixsen
W.
,
Ellis
H.
(
1983
)
Mutations that affect neural cell lineages and cell fates during the development of the nematode C. elegans.
Cold Spring Harbor Symposia on Quantitative Biology
48
,
453
463
Hynes
R. O.
,
Lander
A. D.
(
1992
)
Contact and adhesive specificities in the associations, migrations and targeting of cells and axons.
Cell
68
,
303
322
Ingham
P. W.
(
1991
)
Segment polarity genes and cell patterning within the Drosophila body segment.
Current Opinion in Genetics and Development
1
,
261
267
Kamb
A.
,
Weir
M.
,
Rudy
B.
,
Varmus
H.
,
Kenyon
C.
(
1989
)
Identification of genes from pattern formation, tyrosine kinase, and potassium channel families by DNA amplification.
Proc. Natl. Acad. Sci. USA
86
,
4372
4376
Kenyon
C.
(
1986
)
A gene involved in the development of the posterior body region of C. elegans.
Cell
46
,
477
487
Kenyon
C.
,
Wang
B.
(
1991
)
A cluster of Antennapedia-class homeobox genes in a nonsegmented animal.
Science
253
,
516
517
Lambie
E.
,
Kimble
J.
(
1991
)
Two homologous regulatory genes, lin-12 and glp-1, have overlapping functions.
Development
112
,
231
240
Nusslein-Volhard
C.
,
Wieschaus
E.
(
1980
)
Mutations affecting segment number and polarity in Drosophila.
Nature
287
,
795
801
Oda
H.
,
Uemura
T.
,
Shiomi
K.
,
Nagafuchi
A.
,
Tsukita
S.
,
Takeichi
M.
(
1993
)
Identification of a Drosophila homologue of-catenin and its association with the armadillo protein.
J. Cell Biol
121
,
1133
1140
Peifer
M.
,
McCrea
P. D.
,
Green
K. J.
,
Wieschaus
E.
,
Gumbiner
B. M.
(
1992
)
The vertebrate adhesive junction proteins-catenin and plakoglobin and the Drosophila segment polarity gene armadillo form a multigene family with similar properties.
J. Cell Biol
118
,
681
91
Peifer
M.
,
Wieschaus
E.
(
1990
)
The segment polarity gene armadillo encodes a functionally modular protein that is the Drosophila homologue of human plakoglobin.
Cell
63
,
1167
1178
Priess
J. R.
,
Schnabel
H.
,
Schnabel
R.
(
1987
)
The glp-1 locus and cellular interactions in early C. elegans embryos.
Cell
51
,
601
11
Rijsewijk
F.
,
Schuermann
M.
,
Wagenaar
E.
,
Parren
P.
,
Weigel
D.
,
Nusse
R.
(
1987
)
The Drosophila homologue of the mouse mammary oncogene int-1 is identical to the segment polarity gene wingless.
Cell
50
,
649
657
Salser
S.
,
Kenyon
C.
(
1992
)
Activation of a C. elegans Antennapedia homologue in migrating cells controls their direction of migration.
Nature
355
,
255
258
Salser
S. J.
,
Loer
C. M.
,
Kenyon
C.
(
1993
)
Multiple HOM-C gene interactions specify cell fates in the nematode CNS.
Genes Dev
7
,
1714
1724
Shackleford
G. M.
,
Shivakumar
S.
,
Shuie
L.
,
Mason
J.
,
Kenyon
C.
,
Varmus
H. E.
(
1993
)
Two wnt genes in Caenorhabditis elegans.
Oncogene
(in press).
Sulston
J.
,
Horvitz
H.
(
1977
).
Post-embryonic cell lineages of the nematode, C. elegans.
Dev. Biol
56
,
110
156
Sulston
J.
,
White
J.
(
1980
)
Regulation and cell autonomy during postembryonic development of C. elegans.
Dev. Biol
78
,
577
597
Wang
B. B.
,
Muller-Immergluck
M. M.
,
Austin
J.
,
Robinson
N. T.
,
Chisholm
A.
,
Kenyon
C.
(
1993
)
A homeotic gene cluster patterns the anteroposterior body axis of C. elegans.
Cell
74
,
29
42
Waring
D. A.
,
Kenyon
C.
(
1990
)
Selective silencing of cell communication influences anteroposterior pattern formation in C. elegans.
Cell
60
,
123
131
Waring
D. A.
,
Kenyon
C.
(
1991
)
Regulation of cellular responsiveness to inductive signals in the developing C. elegans nervous system.
Nature
350
,
712
5
Waring
D. A.
,
Wrischnik
L.
,
Kenyon
C.
(
1992
)
Cell signals allow the expression of a pre-existent neural pattern in C. elegans.
Development
116
,
457
466
Way
J.
,
Chalfie
M.
(
1988
)
mec-3, a homeobox-containing gene that specifies differentiation of the touch receptor neurons in C. elegans.
Cell
54
,
5
16
Yochem
J.
,
Greenwald
I.
(
1989
)
glp-1 and lin-12, genes implicated in distinct cell-cell interactions in C. elegans, encode similar transmembrane proteins.
Cell
58
,
553
563
Yochem
J.
,
Weston
K.
,
Greenwald
I.
(
1988
)
The C. eleganslin-12 gene encodes a transmembrane protein with overall similarity to Drosophila Notch.
Nature
335
,
547
550
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