Schaller CWD et al. (1991) International C. elegans Meeting "Ceh-13: structurally labial. What about its expression ?"

Schaller CWD, Spicher A, Mueller F, Tobler H

[International C. elegans Meeting, 1991]

Homeobox-containing genes control cell identities in particular spatial domains, cell lineages, or cell types during the development of Drosophila and Caenorhabditis elegans; they probably control similar processes in vertebrates. The number of ceh genes (C. elegans homeobox-containing genes) is estimated to be at least sixtv, corresponding to about one percent of the total gene number (Burglin et al, Nature 341, 239-243, 1989). Using ceh-l 1 (there is growing evidence that it is part of egl-S, Bruce Wang and Cynthia Kenyon, WBG 11 no 5,1991) as a probe, we isolated ceh-13 from a cDNA library of eggs. J. Sulston and A. Coulson (personal communication) have located it next to other ceh genes on the third chromosome, suggesting that in C. elegans at least some homeoboxcontaining genes are organized in clusters, comparable to the large clusters of homeoboxes known to exist in insects and vertebrates. Ceh-13 is evolutionarily related to the labial class of homeoboxes. Studying its expression should reveal whether the corresponding protein is required for the normal development of the anterior part of C.elegans embryos, as is the case for the labial protein in Drosophila embryos and for its counterparts in mouse and chicken. If so, a functional and not just a structural parallel between homeobox-containing genes in C.elegans, Drosophila and vertebrates could be established.

Wittmann C et al. (1989) International C. elegans Meeting "homeobox-containing genes in C elegans."

Tobler H, Mueller F, Wittmann C, Spicher A, Schaller CWD

[International C. elegans Meeting, 1989]

Wang BB et al. (1991) International C. elegans Meeting "An update on the mab-5 complex"

Kenyon CJ, Wang BB

[International C. elegans Meeting, 1991]

We are interested in determining whether C. elegans contains a complex of homeobox-containing genes similar to those found in Drosophila and in vertebrates. The order of the Drosophila homeotic selector genes in the Antennapedia and Bithorax complexes correlates with the order of their expression along the anterior-posterior axis of the embryo. Likewise, the vertebrate homologues of these genes are grouped into complexes and, as shown in the mouse, their chromosomal organization also correlates with their domains of expression. Previous work in our lab on mab-5, an Antp-like homeobox gene responsible for the normal specification of cells in the posterior body region, and more recent work by several labs on ceh-13, egl-5 and lin-39, suggest that a similar complex may exist in C. elegans ( discussed in Wang and Kenyon, WBG 11:5). The chromosomal positions and homeobox sequences of ceh-15, mab-5 and ceh-ll are analogous to the organization of homeobox genes in the Drosophila and vertebrate complexes. (WBG 11:5) We have now determined that ceh-13, a homeobox gene with lab-like homology (Schaller, et al., Nuc. Acids Res. 18:2033), is located to the left of ceh-15, also analogous to the organization in the Drosophila and vertebrate complexes. We are probing about 20 overlapping cosmids spanning the mab-5 region (mec-14 to egl-45) with degenerate homeobox-specific oligos described by Burglin, et al. (Nature 341:239) in order to identify more homeobox genes that may be a part of the mab-5 complex. Preliminary hybridization data suggest that there could be several additional Antp-like homeobox genes in the region.