title: BMP signaling is required for the generation of primordial germ cells in an insect.
abstract: Two modes of germ cell formation are known in animals. Specification through maternally inherited germ plasm occurs in many well-characterized model organisms, but most animals lack germ plasm by morphological and functional criteria. The only known alternative mechanism is induction, experimentally described only in mice, which specify germ cells through bone morphogenetic protein (BMP) signal-mediated induction of a subpopulation of mesodermal cells. Until this report, no experimental evidence of an inductive germ cell signal for specification has been available outside of vertebrates. Here we provide functional genetic experimental evidence consistent with a role for BMP signaling in germ cell formation in a basally branching insect. We show that primordial germ cells of the cricket Gryllus bimaculatus transduce BMP signals and require BMP pathway activity for their formation. Moreover, increased BMP activity leads to ectopic and supernumerary germ cells. Given the commonality of BMP signaling in mouse and cricket germ cell induction, we suggest that BMP-based germ cell formation may be a shared ancestral mechanism in animals.
authors.affiliation: Departments of Organismic and Evolutionary Biology and Molecular and Cellular Biology, Harvard University, Cambridge, MA 02138.
authors.forename: Seth
authors.initials: S
authors.lastname: Donoughe
authors.forename: Taro
authors.initials: T
authors.lastname: Nakamura
authors.forename: Ben
authors.initials: B
authors.lastname: Ewen-Campen
authors.forename: Delbert A
authors.initials: DA
authors.lastname: Green
authors.forename: Lory
authors.initials: L
authors.lastname: Henderson
authors.forename: Cassandra G
authors.initials: CG
authors.lastname: Extavour
mesh_terms: D000818:Animals; D001483:Base Sequence; D019485:Bone Morphogenetic Proteins / Q000378:metabolism*; D003001:Cloning, Molecular; D017931:DNA Primers / Q000235:genetics; D005854:Germ Cells / Q000166:cytology*; D006135:Gryllidae / Q000235:genetics* / Q000502:physiology; D007091:Image Processing, Computer-Assisted; D017403:In Situ Hybridization; D018613:Microscopy, Confocal; D008969:Molecular Sequence Data; D010802:Phylogeny; D016133:Polymerase Chain Reaction / Q000379:methods; D034622:RNA Interference; D017422:Sequence Analysis, DNA; D015398:Signal Transduction / Q000502:physiology*
chemical_list: D019485:Bone Morphogenetic Proteins; D017931:DNA Primers
keywords: Orthoptera; TGF-β; germ line; inductive signaling; piwi