Confocal Imaging of the Microtubule Cytoskeleton in C. elegans Embryos and Germ Cells

The germ line is the only tissue in Caenorhabditis elegans in which a stem cell population continues to divide mitotically throughout life; hence the cell cycles of the germ line and the soma are regulated differently. Here we report the genetic and phenotypic characterization of the glp-3 gene. In animals homozygous for each of five recessive loss-of-function alleles, germ cells in both hermaphrodites and males fail to progress through mitosis and meiosis, but somatic cells appear to divide normally. Germ cells in animals grown at 15° appear by DAPI staining to be uniformly arrested at the G2/M transition with <20 germ cells per gonad on average, suggesting a checkpoint-mediated arrest. In contrast, germ cells in mutant animals grown at 25° frequently proliferate slowly during adulthood, eventually forming small germ lines with several hundred germ cells. Nevertheless, cells in these small germ lines never undergo meiosis. Double mutant analysis with mutations in other genes affecting germ cell proliferation supports the idea that glp-3 may encode a gene product that is required for the mitotic and meiotic cell cycles in the C. elegans germ line.

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Perinuclear P granules are the principal sites of mRNA export in adult C. elegans germ cells

Development ◽

10.1242/dev.044255 ◽

2010 ◽

Vol 137 (8) ◽

pp. 1305-1314 ◽

Cited By ~ 102

Author(s):

U. Sheth ◽

J. Pitt ◽

S. Dennis ◽

J. R. Priess

Keyword(s):

Germ Cells ◽

Mrna Export ◽

P Granules ◽

C Elegans

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Genetic control of programmed cell death in the Caenorhabditis elegans hermaphrodite germline

Development ◽

10.1242/dev.126.5.1011 ◽

1999 ◽

Vol 126 (5) ◽

pp. 1011-1022 ◽

Cited By ~ 8

Author(s):

T.L. Gumienny ◽

E. Lambie ◽

E. Hartwieg ◽

H.R. Horvitz ◽

M.O. Hengartner

Keyword(s):

Cell Death ◽

Caenorhabditis Elegans ◽

Germ Cell ◽

Somatic Cell ◽

Cell Fate ◽

Germ Cells ◽

Mapk Pathway ◽

Apoptotic Cell ◽

C Elegans ◽

Pathway Activation

Development of the nematode Caenorhabditis elegans is highly reproducible and the fate of every somatic cell has been reported. We describe here a previously uncharacterized cell fate in C. elegans: we show that germ cells, which in hermaphrodites can differentiate into sperm and oocytes, also undergo apoptotic cell death. In adult hermaphrodites, over 300 germ cells die, using the same apoptotic execution machinery (ced-3, ced-4 and ced-9) as the previously described 131 somatic cell deaths. However, this machinery is activated by a distinct pathway, as loss of egl-1 function, which inhibits somatic cell death, does not affect germ cell apoptosis. Germ cell death requires ras/MAPK pathway activation and is used to maintain germline homeostasis. We suggest that apoptosis eliminates excess germ cells that acted as nurse cells to provide cytoplasmic components to maturing oocytes.

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DEPS-1 promotes P-granule assembly and RNA interference in C. elegans germ cells

Development ◽

10.1242/dev.015552 ◽

2008 ◽

Vol 135 (5) ◽

pp. 983-993 ◽

Cited By ~ 49

Author(s):

C. A. Spike ◽

J. Bader ◽

V. Reinke ◽

S. Strome

Keyword(s):

Rna Interference ◽

Germ Cells ◽

C Elegans

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Analysis of RNA associated with P granules in germ cells of C. elegans adults

Development ◽

10.1242/dev.128.8.1287 ◽

2001 ◽

Vol 128 (8) ◽

pp. 1287-1298 ◽

Cited By ~ 4

Author(s):

J.A. Schisa ◽

J.N. Pitt ◽

J.R. Priess

Keyword(s):

Germ Cells ◽

Rna Binding ◽

Nuclear Surface ◽

Binding Motifs ◽

P Granules ◽

C Elegans ◽

Specific Mrnas ◽

Tubulin Mrna ◽

Protein Components ◽

Cytoplasmic Structures

P granules are cytoplasmic structures of unknown function that are associated with germ nuclei in the C. elegans gonad, and are localized exclusively to germ cells, or germ cell precursors, throughout the life cycle. All the known protein components of P granules contain putative RNA-binding motifs, suggesting that RNA is involved in either the structure or function of the granules. However, no specific mRNAs have been identified within P granules in the gonad. We show here that P granules normally contain a low level of RNA, and describe conditions that increase this level. We present evidence that several, diverse mRNAs, including pos-1, mex-1, par-3, skn-1, nos-2 and gld-1 mRNA, are present at least transiently within P granules. In contrast, actin and tubulin mRNA and rRNA are either not present in P granules, or are present at relatively low levels. We show that pgl-1 and the glh (Vasa-related) gene family, which encode protein components of P granules, do not appear essential for RNA to concentrate in P granules; these proteins may instead function in events that are a prerequisite for RNAs to be transported efficiently from the nuclear surface.

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C. elegans germ cells divide and differentiate in a folded tissue

Developmental Biology ◽

10.1016/j.ydbio.2018.07.013 ◽

2018 ◽

Vol 442 (1) ◽

pp. 173-187 ◽

Cited By ~ 8

Author(s):

Hannah S. Seidel ◽

Tilmira A. Smith ◽

Jessica K. Evans ◽

Jarred Q. Stamper ◽

Thomas G. Mast ◽

...

Keyword(s):

Germ Cells ◽

C Elegans

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Melting dsDNA donor molecules potentiates precision genome editing in C. elegans

10.1101/2020.08.03.235036 ◽

2020 ◽

Author(s):

Krishna S. Ghanta ◽

Craig C. Mello

Keyword(s):

Caenorhabditis Elegans ◽

Genome Editing ◽

Germ Cells ◽

Multiple Injections ◽

C Elegans ◽

Homology Directed Repair ◽

Selection Strategies ◽

Double Stranded Dna ◽

Adult Hermaphrodite

ABSTRACTCRISPR genome editing has revolutionized genetics in many organisms. In the nematode Caenorhabditis elegans one injection into each of the two gonad arms of an adult hermaphrodite exposes hundreds of meiotic germ cells to editing mixtures, permitting the recovery of multiple indels or small precision edits from each successfully injected animal. Unfortunately, particularly for long insertions, editing efficiencies can vary widely, necessitating multiple injections, and often requiring co-selection strategies. Here we show that melting double stranded DNA (dsDNA) donor molecules prior to injection increases the frequency of precise homology-directed repair (HDR) by several fold for longer edits. We describe troubleshooting strategies that enable consistently high editing efficiencies resulting, for example, in up to 100 independent GFP knock-ins from a single injected animal. These efficiencies make C. elegans by far the easiest metazoan to genome edit, removing barriers to the use and adoption of this facile system as a model for understanding animal biology.

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PUF-8 negatively regulates RAS/MAPK signalling to promote differentiation of C. elegans germ cells

Development ◽

10.1242/dev.088013 ◽

2013 ◽

Vol 140 (8) ◽

pp. 1645-1654 ◽

Cited By ~ 20

Author(s):

S. Vaid ◽

M. Ariz ◽

A. Chaturbedi ◽

G. A. Kumar ◽

K. Subramaniam

Keyword(s):

Germ Cells ◽

C Elegans ◽

Mapk Signalling

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Progression from a stem cell–like state to early differentiation in the C. elegans germ line

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.0912704107 ◽

2010 ◽

Vol 107 (5) ◽

pp. 2048-2053 ◽

Cited By ~ 67

Author(s):

Olivier Cinquin ◽

Sarah L. Crittenden ◽

Dyan E. Morgan ◽

Judith Kimble

Keyword(s):

Stem Cell ◽

Germ Cells ◽

Cell Biology ◽

Germ Line ◽

Stem Cell Biology ◽

Self Renewal ◽

Early Differentiation ◽

C Elegans ◽

Stem Cell Maintenance ◽

System A

Controls of stem cell maintenance and early differentiation are known in several systems. However, the progression from stem cell self-renewal to overt signs of early differentiation is a poorly understood but important problem in stem cell biology. The Caenorhabditis elegans germ line provides a genetically defined model for studying that progression. In this system, a single-celled mesenchymal niche, the distal tip cell (DTC), employs GLP-1/Notch signaling and an RNA regulatory network to balance self-renewal and early differentiation within the “mitotic region,” which continuously self-renews while generating new gametes. Here, we investigate germ cells in the mitotic region for their capacity to differentiate and their state of maturation. Two distinct pools emerge. The “distal pool” is maintained by the DTC in an essentially uniform and immature or “stem cell–like” state; the “proximal pool,” by contrast, contains cells that are maturing toward early differentiation and are likely transit-amplifying cells. A rough estimate of pool sizes is 30–70 germ cells in the distal immature pool and ≈150 in the proximal transit-amplifying pool. We present a simple model for how the network underlying the switch between self-renewal and early differentiation may be acting in these two pools. According to our model, the self-renewal mode of the network maintains the distal pool in an immature state, whereas the transition between self-renewal and early differentiation modes of the network underlies the graded maturation of germ cells in the proximal pool. We discuss implications of this model for controls of stem cells more broadly.

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