The Caenorhabditis elegans LIN-26 protein is required to specify and/or maintain the fates of all non-neuronal ectodermal cells. Here we show that lin-26 is expressed until the somatic gonad primordium stage in all cells of the somatic gonad, except in distal tip cells, and later in all uterine cells. To determine if lin-26 functions in the somatic gonad, we have generated gonad-specific lin-26 alleles obtained by integration of lin-26 promoter deletion derivatives into a lin-26 null mutant background. In this way, we rescued the lethal phenotype imparted by lin-26 null mutations and uncovered a highly penetrant sterile phenotype. Specifically, the strongest of these new alleles was characterized by the absence of lin-26 expression in the somatic gonad, the presence of endomitotic oocytes, decreased germline proliferation, a protruding vulva and a less penetrant absence of gonad arms. Lineage analysis of mutant somatic gonads and examination of several markers expressed in the spermatheca, sheath cells, distal tip cells and the uterus, suggest that LIN-26 is required in sheath, spermatheca and uterine precursors, and in uterine cells. We conclude that lin-26 performs a similar function in the non-neuronal ectoderm and the somatic gonad, a mesoderm derivative, and we speculate that lin-26 is required to express epithelial characteristics.

REFERENCES

REFERENCES
Basson
M.
,
Horvitz
H. R.
(
1996
)
The Caenorhabditis elegans gene sem-4 controls neuronal and mesodermal cell development and encodes a zinc finger protein.
Genes Dev
10
,
1953
1965
Boyle
M.
,
Bonini
N.
,
DiNardo
S.
(
1997
)
Expression and function of clift in the development of somatic gonadal precursors within the Drosophila mesoderm.
Development
124
,
971
982
Brenner
S.
(
1974
)
The genetics of Caenorhabditis elegans.
Genetics
77
,
71
94
Chanal
P.
,
Labouesse
M.
(
1997
)
A screen for genetic loci required for hypodermal cell and glial-like cell development during Caenorhabditis elegans embryogenesis.
Genetics,
146
,
207
226
Davies
J. A.
,
Garrod
D. R.
(
1997
)
Molecular aspects of the epithelial phenotype.
BioEssays
19
,
699
704
Felix
M.-A.
,
Sternberg
P. W.
(
1996
)
Symmetry breakage in the development of one-armed gonads in nematodes.
Development
122
,
2129
2142
Finney
M.
,
Ruvkun
G.
(
1990
)
The unc-86 gene product couples cell lineage and cell identity in C. elegans.
Cell
63
,
895
905
Francis
R.
,
Waterston
R.
(
1991
)
Muscle cell attachment in Caenorhabditis elegans.
J. Cell Biol
114
,
465
479
Francis
R.
,
Barton
M. K.
,
Kimble
J.
,
Schedl
T.
(
1995
)
gld-1, a tumor suppressor gene required for oocyte development in Caenorhabditiselegans.
Genetics
139
,
579
606
Freyd
G.
,
Kim
S. K.
,
Horvitz
H. R.
(
1990
)
Novel cysteine-rich motifand homeodomain in the product of the Caenorhabditis elegans cell lineage gene lin-11.
Nature
344
,
876
879
Greenstein
D.
,
Hird
S.
,
Plasterk
R. H. A.
,
Andachi
Y.
,
Kohara
Y.
,
Wang
B.
,
Finney
M.
,
Ruvkun
G.
(
1994
)
Targeted mutations in the Caenorhabditis elegans POU homeo box gene ceh-18 cause defects in oocyte cell cycle arrest, gonad migration, and epidermal differentiation.
Genes Dev
8
,
1935
1948
Greenwald
I. S.
,
Sternberg
P. W.
,
Horvitz
H. R.
(
1983
)
The lin-12 locus specifies cell fates in C. elegans.
Cell
34
,
435
444
Hengartner
M. O.
,
Horvitz
H. R.
(
1994
)
Programmed cell death in Caenorhabditis elegans.
Curr. Opin. Genet. Dev
4
,
581
586
Hirsh
D.
,
Oppenheim
D.
,
Klass
M.
(
1976
)
Development of the reproductive system of C. elegans.
Dev. Biol
49
,
200
219
Hope
I. A.
(
1991
)
Promoter trapping in Caenorhabditis elegans.
Development
113
,
399
408
Kimble
J.
,
Hirsh
D.
(
1979
)
Postembryonic cell lineages of the hermaphrodite and male gonads in Caenorhabditis elegans.
Dev. Biol
70
,
396
417
Labouesse
M.
,
Sookhareea
S.
,
Horvitz
H. R.
(
1994
)
The Caenorhabditis elegans gene lin-26 is required to specify the fates of hypodermal cells and encodes a presumptive zinc-finger transcription factor.
Development
120
,
2359
2368
Labouesse
M.
,
Hartwieg
E.
,
Horvitz
H. R.
(
1996
)
The Caenorhabditis elegans LIN-26 protein is required to specify and/or maintain all fates.
Development
122
,
2579
2588
Lambie
E. J.
,
Kimble
J.
(
1991
)
Two homologous regulatory genes, lin-12 and glp-1, have overlapping functions.
Development
122
,
231
240
McCarter
J.
,
Bartlett
B.
,
Dang
T.
,
Schedl
T.
(
1997
)
Soma-germ cell interactions in Caenorhabditis elegans: multiple events of hermaphrodite germline development require the somatic sheath and spermatheca lineages.
Dev. Biol
181
,
121
143
Newman
A. P.
,
White
J. G.
,
Sternberg
P. W.
(
1995
)
The Caenorhabditis eleganslin-12 gene mediates induction of ventral uterine specialization by the anchor cell.
Development
121
,
263
271
Newman
A. P.
,
White
J. G.
,
Sternberg
P. W.
(
1996
)
Morphogenesis of the C. elegans hermaphrodite uterus.
Development
122
,
3617
3626
Rose
K. L.
,
Winfrey
V. P.
,
Hoffman
L. H.
,
Hall
D. H.
,
Furuta
T.
,
Greenstein
D.
(
1997
)
The POU gene ceh-18 promotes gonadal sheath cell differentiation and function required for meiotic maturation and ovulation in Caenorhabditis elegans.
Dev. Biol
192
,
59
77
Seydoux
G.
,
Savage
C.
,
Greenwald
I.
(
1993
)
Isolation and characterization of mutations causing abnormal eversion of the vulva in Caenorhabditis elegans.
Dev. Biol
157
,
423
436
Simpson
P.
(
1993
)
Use of a yeast site-specific recombinase to generate embryonic mosaics in Drosophila.
Trends Genet
9
,
227
228
Spencer
D. M.
(
1997
)
Creating conditional mutations in mammals.
Trends Genet
12
,
181
187
Sternberg
P. W.
,
Horvitz
H. R.
(
1988
)
lin-17 mutations of C. elegans disrupt asymmetric cell divisions.
Dev. Biol
130
,
67
73
Strome
S.
(
1986
)
Fluorescence visualization of the distribution of microfilaments in gonads and early embryos of the nematode C. elegans.
J. Cell Biol
103
,
2241
2252
Sulston
J.
,
Horvitz
H. R.
(
1977
)
Postembryonic cell lineages of the nematode Caenorhabditis elegans.
Dev. Biol
56
,
110
156
Sulston
J. E.
,
Schierenberg
E.
,
White
J. G.
,
Thomson
J. N.
(
1983
)
The embryonic cell lineage of the nematode Caenorhabditis elegans.
Dev. Biol
100
,
64
119
Zwaal
R. R.
,
Broeks
A.
,
van Meurs
J.
,
Groenen
J. T. M.
,
Plasterk
R. A. H.
(
1993
)
Target-selected gene inactivation in Caenorhabditis elegans by using a frozen transposon insertion mutant bank.
Proc. Natl. Acad. Sci. USA
90
,
7431
7435
This content is only available via PDF.