Caenorhabditis elegans Embryo: Determination of Somatic Cell Fate


Although embryogenesis appears to be determinate in C. elegans because of its stereotype cell lineage, the mechanisms of regional specification typical for indeterminate development are nevertheless used. Early on, blastomere identities are specified by binary decisions, and each blastomere gives rise to a coherent region of the embryo containing different somatic cell fates.

Keywords: regional specification; binary switch; pattern formation; tissue specification; cell lineage; 4‐dimensional microscopy

Figure 1.

Foundercell formation in Caenorhabditis elegans. (a) During the first fourdivision cleavages the fertilized zygote gives rise to the somatic foundercells in asymmetric divisions. The major tissues produced by the founder cellsare indicated. MS and C also produce some neurons. (b) Schematicrepresentation of the first divisions of the embryo. The first threeinductions specifying the AB lineage are indicated. Two later inductionsspecify minor left–right asymmetries in the AB lineage. These inductionsspecify blastomere identities corresponding to regions later in the larva (see Schnabeland Priess, ).

Figure 2.

Regionalorganization of the Caenorhabditis elegans embryo. (a) Twelve‐cellstage embryo. The lineage descent of cells is colour coded as shown at thebottom of the figure. (b) Dorsal, ventral left and right view of an embryo atthe premorphogenetic stage (380 cells). The descendants of the earlyblastomeres populate coherent regions. No mixing of the descendants ofblastomeres of the 12‐cell stage occurs. Cells form the regions by cellmigrations. (c) Three views of an embryo created in a computer simulation (M.Gumpel, unpublished). The blastomeres of the 12‐cell embryo shown in (a) weredivided only in the anterior–posterior direction. The descendantsintermingle and no coherent regions form. The specific arrangement of regionsin the C. elegans embryo therefore requires active sorting processes.(d) Arrangement of cells within a region at the premorphogenetic stage.Descendants of ABplpaa (red), ABplpap (yellow), ABplppa (green) and ABplpppp(blue) are shown. The anterior descendants of the next cleavage are shown witha lighter, the posterior ones with a darker tint. As indicated for the mostanterior lineages cells are not strictly arranged according to their lineagedescent within a region.

Figure 3.

The lineageproduces cell fates according to the positional requirements. The figure showsthe anterior part of a premorphogenetic embryo. Yellow nuclei (spheres),nervous system; blue, pharyngeal cells; green, intestine; grey,nonpharyngeal MS‐derived nuclei. The pharynx precursor is also outlined. TheMSaa derived cells (colour coded from red to orange) span through the anteriorof the embryo. The most anterior cell present at the premorphogenetic stagelies outside of the pharynx and later produces two neurons which contribute tothe part of the nervous system formed in this area from ABala. The two mostposterior cells are placed, like the most anterior, outside the pharynx andproduce body wall muscle. As indicated at the top of the figure the pharyngealcells acquire the fates needed in the specific positions to produce afunctional pharynx, for example at the margin of the intestine valve cells aremade which connect pharynx and intestine. The 28 cells derived from MSaapresent at this stage produce seven different tissues. The fates must bespecified primarily by positional criteria. The complex differentiationpattern indicates that no grouping according to cell fate occurs in thelineage.



Ahnn J and Fire A (1994) A screen for genetic loci required for body‐wall muscle development during embryogenesis in Caenorhabditis elegans. Genetics 137: 483–498.

Ahringer J (1997) Maternal control of a zygotic patterning gene in Caenorhabditis elegans. Development 124: 3865–3869.

Evans TC, Crittenden SL, Kodoyianni V and Kimble J (1994) Translational control of maternal glp‐1 mRNA establishes an asymmetry in the C. elegans embryo. Cell 77: 183–194.

Fukushige T, Hawkins MG and McGhee JD (1998) The GATA‐factor elt‐2 is essential for the formation of the Caenorhabditis elegans intestine. Developmental Biology 198: 286–302.

Hunter CP and Kenyon C (1996) Spatial and temporal controls target pal‐1 blastomere‐specification activity to a single blastomere lineage in C. elegans embryos. Cell 87: 217–226.

Kalb JM, Lau KK, Goszcynski B et al. (1998) pha‐4 is Ce‐fkh‐1, a fork head/HNF‐3 alpha, beta, gamma homolog that functions in organogenesis of the C elegans pharynx. Development 125: 2171–2180.

Kaletta T, Schnabel H and Schnabel R (1997) Binary specification of the embryonic lineage in Caenorhabditis elegans. Nature 390: 294–298.

Labouesse M and Mango SE (1999) Patterning the C. elegans embryo: moving beyond the cell lineage. Trends in Genetics 15: 307–313.

Lin R, Hill RJ and Priess JR (1998) POP‐1 and anterior‐posterior fate decisions in C. elegans embryos. Cell 92: 229–239.

Meneghini MD, Ishitami T, Carter JC et al. (1999) MAP kinase and WNT pathways converge to downregulate an HMG‐domain repressor in Caenorhabditis elegans. Nature 399: 793–797.

Rocheleau CE, Yasuda J, Shin TH et al. (1999) WRM‐1 activates the LIT‐1 protein kinase to transduce anterior/posterior polarity signals in C. elegans. Cell 97: 717–726.

Schroeder DF and McGhee JD (1998) Anterior–posterior patterning within the Caenorhabditis elegans endoderm. Development 125: 4877–4887.

Schnabel R (1997) Why does a nematode have an invariant cell lineage? Seminars in Cell and Developmental Biology 8: 341–349.

Schnabel R and Priess JR (1997) Specification of cell fates in the early embryo. In: Riddle DL, Blumenthal T, Meyer BJ and Priess JR (eds) C. elegans II, pp. 361–382. Cold Spring Harbor, Ny: Cold Spring Harbor Laboratory Press.

Schnabel R, Hutter H, Moerman DG and Schnabel H (1997) Assessing normal embryogenesis in C. elegans using a 4D‐microscope: variability of development and regional specification. Developmental Biology 184: 234–265.

Sulston JE, Schierenberg E, White JG and Thomson JN (1983) The embryonic cell lineage of the nematode Caenorhabditis elegans. Developmental Biology 100: 64–119.

Further Reading

Bowerman B and Shelton CA (1999) Cell polarity in the early C. elegans embryo. Current Opinion in Genetics and Development 9: 390–395.

Newman‐Smith ED and Rothman JH (1998) The maternal‐to‐zygotic transition in embryonic patterning of C. elegans. Current Opinion in Genetics and Development 8: 472–478.

Rose LS and Kemphues KJ (1998) Early patterning of the C. elegans embryo. Annual Review of Genetics 32: 521–545.

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Schnabel, Ralf(Mar 2003) Caenorhabditis elegans Embryo: Determination of Somatic Cell Fate. In: eLS. John Wiley & Sons Ltd, Chichester. [doi: 10.1038/npg.els.0001507]