title: Temperature-dependent activation of ERK/MAPK in yolk cells and its role in embryonic diapause termination in the silkworm Bombyx mori.
abstract: The silkworm Bombyx mori requires 2-3 months of low temperature (5 degrees C) to terminate embryonic diapause. The molecular mechanisms, however, are unknown. Extracellular signal-regulated kinase (ERK)/mitogen-activated protein kinase (MAPK) is temperature-dependently activated in the yolk cells of diapausing eggs after 45 days at 5 degrees C, coincident with the acquisition of developmental competence of the embryos at 25 degrees C. Yolk cell granulation and dissociation also begin in diapause eggs incubated at 5 degrees C for 45 days. We used dechorionated egg culture as a model system of diapause termination and observed that both yolk cell dissociation and embryonic development are inhibited by MAPK-ERK kinase (MEK) inhibitor U0126. Therefore, we suggest that ERK in yolk cells has a role in regulating changes in yolk morphology and termination of embryonic diapause in B. mori.
authors.affiliation: Division of Molecular Science, Graduate School of Science and Technology, Kobe University, Nada, Japan.
authors.forename: Ken-ichi
authors.initials: K
authors.lastname: Iwata
authors.forename: Chiyomi
authors.initials: C
authors.lastname: Shindome
authors.forename: Yuki
authors.initials: Y
authors.lastname: Kobayashi
authors.forename: Makio
authors.initials: M
authors.lastname: Takeda
authors.forename: Okitsugu
authors.initials: O
authors.lastname: Yamashita
authors.forename: Kunihiro
authors.initials: K
authors.lastname: Shiomi
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Fujiwara
mesh_terms: D000222:Adaptation, Physiological / Q000502:physiology*; D000818:Animals; D015153:Blotting, Western; D012831:Bombyx / Q000187:drug effects / Q000196:embryology* / Q000201:enzymology; D002070:Butadienes / Q000633:toxicity; D004789:Enzyme Activation / Q000502:physiology; D048049:Extracellular Signal-Regulated MAP Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D007150:Immunohistochemistry; D009570:Nitriles / Q000633:toxicity; D010063:Ovum / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D010766:Phosphorylation / Q000187:drug effects; D013696:Temperature
chemical_list: D002070:Butadienes; D009570:Nitriles; C113580:U 0126; D048049:Extracellular Signal-Regulated MAP Kinases