title: Formation of the egg-laying system in Pristionchus pacificus requires complex interactions between gonadal, mesodermal and epidermal tissues and does not rely on single cell inductions.
abstract: The invariant cell lineage of nematodes allows the formation of organ systems, like the egg-laying system, to be studied at a single cell level. The Caenorhabditis elegans egg-laying system is made up of the vulva, the mesodermal gonad and muscles and several neurons. The gonad plays a central role in patterning the underlying ectoderm to form the vulva and guiding the migration of the sex myoblasts to their final position. In Pristionchus pacificus, the egg-laying system is homologous to C. elegans, but comparative studies revealed several differences at the cellular and molecular levels during vulval formation. For example, the mesoblast M participates in lateral inhibition, a process that influences the fate of two vulval precursor cells. Here, we describe the M lineage in Pristionchus and show that both the dorsal and ventral M sublineages are involved in lateral inhibition. Mutations in the homeotic gene Ppa-mab-5 cause severe misspecification of the M lineage, resembling more the C. elegans Twist than the mab-5 phenotype. Ectopic differentiation of P8.p in Ppa-mab-5 results from at least two separate interactions between M and P8.p. Thus, interactions among the Pristionchus egg-laying system are complex, involving multiple cells of different tissues occurring over a distance.
authors.affiliation: Max-Planck Institut für Entwicklungsbiologie, Abteilung Evolutionsbiologie, Spemannstrasse 37-39, D-72076 Tübingen, Germany.
authors.forename: B
authors.initials: B
authors.lastname: Jungblut
authors.forename: A
authors.initials: A
authors.lastname: Pires-daSilva
authors.forename: R J
authors.initials: RJ
authors.lastname: Sommer
mesh_terms: D000818:Animals; D005075:Biological Evolution; D019521:Body Patterning; D029742:Caenorhabditis elegans Proteins; D002450:Cell Communication; D019070:Cell Lineage; D004817:Epidermis / Q000502:physiology; D005260:Female; D005801:Genes, Homeobox; D018398:Homeodomain Proteins / Q000235:genetics; D008648:Mesoderm / Q000502:physiology; D009348:Nematoda / Q000196:embryology*; D010053:Ovary / Q000196:embryology*; D010058:Oviposition / Q000502:physiology*; D013045:Species Specificity; D013234:Stem Cells; D014157:Transcription Factors / Q000235:genetics; D014844:Vulva / Q000196:embryology*
chemical_list: D029742:Caenorhabditis elegans Proteins; D018398:Homeodomain Proteins; C081538:Mab-5 protein, C elegans; D014157:Transcription Factors