title: Ancestral functions of Delta/Notch signaling in the formation of body and leg segments in the cricket Gryllus bimaculatus.
abstract: Delta/Notch signaling controls a wide spectrum of developmental processes, including body and leg segmentation in arthropods. The various functions of Delta/Notch signaling vary among species. For instance, in Cupiennius spiders, Delta/Notch signaling is essential for body and leg segmentation, whereas in Drosophila fruit flies it is involved in leg segmentation but not body segmentation. Therefore, to gain further insight into the functional evolution of Delta/Notch signaling in arthropod body and leg segmentation, we analyzed the function of the Delta (Gb'Delta) and Notch (Gb'Notch) genes in the hemimetabolous, intermediate-germ cricket Gryllus bimaculatus. We found that Gb'Delta and Gb'Notch were expressed in developing legs, and that RNAi silencing of Gb'Notch resulted in a marked reduction in leg length with a loss of joints. Our results suggest that the role of Notch signaling in leg segmentation is conserved in hemimetabolous insects. Furthermore, we found that Gb'Delta was expressed transiently in the posterior growth zone of the germband and in segmental stripes earlier than the appearance of wingless segmental stripes, whereas Gb'Notch was uniformly expressed in early germbands. RNAi knockdown of Gb'Delta or Gb'Notch expression resulted in malformation in body segments and a loss of posterior segments, the latter probably due to a defect in posterior growth. Therefore, in the cricket, Delta/Notch signaling might be required for proper morphogenesis of body segments and posterior elongation, but not for specification of segment boundaries.
authors.affiliation: Department of Life Systems, Institute of Technology and Science, The University of Tokushima, 2-1 Minami-Jyosanjima-cho, Tokushima City, 770-8506 Japan. mito@bio.tokushima-u.ac.jp
authors.forename: Taro
authors.initials: T
authors.lastname: Mito
authors.forename: Yohei
authors.initials: Y
authors.lastname: Shinmyo
authors.forename: Kazuki
authors.initials: K
authors.lastname: Kurita
authors.forename: Taro
authors.initials: T
authors.lastname: Nakamura
authors.forename: Hideyo
authors.initials: H
authors.lastname: Ohuchi
authors.forename: Sumihare
authors.initials: S
authors.lastname: Noji
mesh_terms: D000818:Animals; D019521:Body Patterning / Q000235:genetics / Q000502:physiology; D049109:Cell Proliferation; D004625:Embryo, Nonmammalian / Q000378:metabolism; D047108:Embryonic Development / Q000235:genetics / Q000502:physiology; D005121:Extremities / Q000196:embryology*; D006135:Gryllidae; D007150:Immunohistochemistry; D017403:In Situ Hybridization; D047908:Intracellular Signaling Peptides and Proteins / Q000235:genetics / Q000378:metabolism*; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D034622:RNA Interference; D051880:Receptors, Notch / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction / Q000235:genetics / Q000502:physiology
chemical_list: D047908:Intracellular Signaling Peptides and Proteins; D008565:Membrane Proteins; D051880:Receptors, Notch; C064045:delta protein