title: Steroid-induced oocyte maturation in Indian shad Tenualosa ilisha (Hamilton, 1822) is dependent on phosphatidylinositol 3 kinase but not MAP kinase activation.
abstract: Fully grown fish and amphibian oocytes exposed to a maturation-inducing steroid (MIS) activates multiple signal transduction pathways, leading to formation and activation of maturation-promoting factor (MPF) and induction of germinal vesicle breakdown (GVBD). The present study was to investigate if phosphatidylinositol 3 kinase (PI3 kinase) and mitogen-activated protein kinase (MAP kinase) activation are required for naturally occurring MIS, 17α,20β-dihydroxy-4-pregnen-3-one (17,20β-P)-induced cdc2 activation and oocyte maturation (OM) in Tenualosa ilisha. We observed that 17,20β-P-induced OM was significantly inhibited by PI3 kinase inhibitors Wortmannin and LY29400. 17,20 β-P was shown to activate PI3 kinase maximally at 90 min and cdc2 kinase at 16 h of treatment. Relative involvement of PI3 kinase, MAP kinase and cdc2 kinase in 17,20β-P-induced OM was examined. MAP kinase was rapidly phosphorylated and activated (60-120 min) after MIS treatment and this response preceded the activation of cdc2 kinase by several hours. A selective inhibitor of MAP kinase (MEK), PD98059, sufficiently blocked the phosphorylation and activation of MAP kinase. Inhibition of MAP kinase activity using PD98059 however, had no effect on MIS-induced cdc2 kinase activation and GVBD. These results demonstrate that activation of the PI3 kinase is required for 17,20β-P-induced cdc2 kinase activation and OM in T. ilisha. MAP kinase although was activated in response to 17,20β-P and PI3 kinase activation, it is not necessary for cdc2 activation and OM in this species.
authors.affiliation: Department of Zoology, Presidency University, 86/1 College Street, Kolkata 73, India.
authors.forename: Kousik
authors.initials: K
authors.lastname: Pramanick
authors.affiliation: Department of Physiology and Biophysics, School of Medicine, Health Sciences Center-A, University of Louisville, KY 40292, USA.
authors.forename: Sourav
authors.initials: S
authors.lastname: Kundu
authors.affiliation: Endocrinology Laboratory, Department of Zoology, University of Kalyani, Kalyani 741235, West Bengal, India.
authors.forename: Sudipta
authors.initials: S
authors.lastname: Paul
authors.affiliation: Endocrinology Laboratory, Department of Zoology, University of Kalyani, Kalyani 741235, West Bengal, India.
authors.forename: Buddhadev
authors.initials: B
authors.lastname: Mallick
authors.affiliation: Endocrinology Laboratory, Department of Zoology, University of Kalyani, Kalyani 741235, West Bengal, India.
authors.forename: Sujata
authors.initials: S
authors.lastname: Roy Moulik
authors.affiliation: Endocrinology Laboratory, Department of Zoology, University of Kalyani, Kalyani 741235, West Bengal, India.
authors.forename: Puja
authors.initials: P
authors.lastname: Pal
authors.affiliation: Endocrinology Laboratory, Department of Zoology, University of Kalyani, Kalyani 741235, West Bengal, India. Electronic address: dilipmukher@rediffmail.com.
authors.forename: Dilip
authors.initials: D
authors.lastname: Mukherjee
mesh_terms: D000818:Animals; D016203:CDC2 Protein Kinase / Q000378:metabolism; D002478:Cells, Cultured; D006063:Chorionic Gonadotropin / Q000494:pharmacology / Q000502:physiology; D004789:Enzyme Activation; D005260:Female; D029941:Fish Proteins / Q000378:metabolism*; D005399:Fishes / Q000502:physiology*; D006908:Hydroxyprogesterones / Q000494:pharmacology; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism*; D009865:Oocytes / Q000201:enzymology* / Q000502:physiology; D009866:Oogenesis; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism*; D010766:Phosphorylation; D011499:Protein Processing, Post-Translational; D015398:Signal Transduction
chemical_list: D006063:Chorionic Gonadotropin; D029941:Fish Proteins; D006908:Hydroxyprogesterones; C007433:17,20-dihydroxy-4-pregnen-3-one; D019869:Phosphatidylinositol 3-Kinases; D016203:CDC2 Protein Kinase; D020928:Mitogen-Activated Protein Kinases
keywords: 17,20β-P; MAP kinase; Oocyte maturation; PI3 kinase; Tenulosa ilisha; cdc2 kinase