title: The Rosetteless gene controls development in the choanoflagellate S. rosetta.
abstract: The origin of animal multicellularity may be reconstructed by comparing animals with one of their closest living relatives, the choanoflagellate Salpingoeca rosetta. Just as animals develop from a single cell-the zygote-multicellular rosettes of S. rosetta develop from a founding cell. To investigate rosette development, we established forward genetics in S. rosetta. We find that the rosette defect of one mutant, named Rosetteless, maps to a predicted C-type lectin, a class of signaling and adhesion genes required for the development and innate immunity in animals. Rosetteless protein is essential for rosette development and forms an extracellular layer that coats and connects the basal poles of each cell in rosettes. This study provides the first link between genotype and phenotype in choanoflagellates and raises the possibility that a protein with C-type lectin-like domains regulated development in the last common ancestor of choanoflagellates and animals.
authors.affiliation: Department of Molecular and Cell Biology, Howard Hughes Medical Institute, University of California, Berkeley, Berkeley, United States.
authors.forename: Tera C
authors.identifier: http://orcid.org/0000-0001-7883-8522
authors.initials: TC
authors.lastname: Levin
authors.affiliation: Department of Molecular and Cell Biology, Howard Hughes Medical Institute, University of California, Berkeley, Berkeley, United States.
authors.forename: Allison J
authors.initials: AJ
authors.lastname: Greaney
authors.affiliation: Department of Molecular and Cell Biology, Howard Hughes Medical Institute, University of California, Berkeley, Berkeley, United States.
authors.forename: Laura
authors.initials: L
authors.lastname: Wetzel
authors.affiliation: Department of Molecular and Cell Biology, Howard Hughes Medical Institute, University of California, Berkeley, Berkeley, United States.
authors.forename: Nicole
authors.initials: N
authors.lastname: King
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D056897:Choanoflagellata / Q000235:genetics* / Q000254:growth & development*; D005786:Gene Expression Regulation; D017125:Genes, Protozoan; D037181:Lectins, C-Type / Q000378:metabolism; D008954:Models, Biological; D008969:Molecular Sequence Data; D009154:Mutation / Q000235:genetics; D010641:Phenotype; D015800:Protozoan Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism
chemical_list: D037181:Lectins, C-Type; D015800:Protozoan Proteins
keywords: C-type lectin-like; Salpingoeca rosetta; choanoflagellate; developmental biology; evolutionary biology; genomics; multicellularity; rosetteless; stem cells