title: Role of mef2ca in developmental buffering of the zebrafish larval hyoid dermal skeleton.
abstract: Phenotypic robustness requires a process of developmental buffering that is largely not understood, but which can be disrupted by mutations. Here we show that in mef2ca(b1086) loss of function mutant embryos and early larvae, development of craniofacial hyoid bones, the opercle (Op) and branchiostegal ray (BR), becomes remarkably unstable; the large magnitude of the instability serves as a positive attribute to learn about features of this developmental buffering. The OpBR mutant phenotype variably includes bone expansion and fusion, Op duplication, and BR homeosis. Formation of a novel bone strut, or a bone bridge connecting the Op and BR together occurs frequently. We find no evidence that the phenotypic stability in the wild type is provided by redundancy between mef2ca and its co-ortholog mef2cb, or that it is related to the selector (homeotic) gene function of mef2ca. Changes in dorsal-ventral patterning of the hyoid arch also might not contribute to phenotypic instability in mutants. However, subsequent development of the bone lineage itself, including osteoblast differentiation and morphogenetic outgrowth, shows marked variation. Hence, steps along the developmental trajectory appear differentially sensitive to the loss of buffering, providing focus for the future study.
authors.affiliation: Institute of Neuroscience, 1254 University of Oregon, Eugene, OR 97403-1254, USA.
authors.forename: April
authors.initials: A
authors.lastname: DeLaurier
authors.affiliation: Institute of Neuroscience, 1254 University of Oregon, Eugene, OR 97403-1254, USA.
authors.forename: Tyler R
authors.initials: TR
authors.lastname: Huycke
authors.affiliation: Institute of Neuroscience, 1254 University of Oregon, Eugene, OR 97403-1254, USA.
authors.forename: James T
authors.initials: JT
authors.lastname: Nichols
authors.affiliation: Institute of Neuroscience, 1254 University of Oregon, Eugene, OR 97403-1254, USA.
authors.forename: Mary E
authors.initials: ME
authors.lastname: Swartz
authors.affiliation: Institute of Neuroscience, 1254 University of Oregon, Eugene, OR 97403-1254, USA.
authors.forename: Ashlin
authors.initials: A
authors.lastname: Larsen
authors.affiliation: Institute of Neuroscience, 1254 University of Oregon, Eugene, OR 97403-1254, USA.
authors.forename: Charline
authors.initials: C
authors.lastname: Walker
authors.affiliation: Institute of Neuroscience, 1254 University of Oregon, Eugene, OR 97403-1254, USA.
authors.forename: John
authors.initials: J
authors.lastname: Dowd
authors.affiliation: Division of Basic Science, Fred Hutchinson Cancer Center, 1100 Fairview Ave. N., PO Box 19024, Seattle, WA 98109, USA.
authors.forename: Luyuan
authors.initials: L
authors.lastname: Pan
authors.affiliation: Division of Basic Science, Fred Hutchinson Cancer Center, 1100 Fairview Ave. N., PO Box 19024, Seattle, WA 98109, USA.
authors.forename: Cecilia B
authors.initials: CB
authors.lastname: Moens
authors.affiliation: Institute of Neuroscience, 1254 University of Oregon, Eugene, OR 97403-1254, USA. Electronic address: kimmel@uoneuro.uoregon.edu.
authors.forename: Charles B
authors.initials: CB
authors.lastname: Kimmel
mesh_terms: D000818:Animals; D001846:Bone Development / Q000235:genetics*; D005801:Genes, Homeobox; D007814:Larva / Q000254:growth & development*; D015027:Zebrafish / Q000196:embryology* / Q000235:genetics / Q000254:growth & development; D029961:Zebrafish Proteins / Q000235:genetics*
chemical_list: D029961:Zebrafish Proteins
keywords: Canalization; Developmental instability; Osteoblast; Pharyngeal arch; Skeleton; mef2c