title: Tissue preferential expression of estrogen receptor gene in the marine snail, Thais clavigera.
abstract: Sex steroid hormones have been widely detected in molluscs, and experiments have shown the importance of sex steroids in sex determination, gonadal tissue maturation and gametogenesis. Nevertheless, the signaling pathways of sex steroids in invertebrates have not yet been elucidated. In order to gain insights into the mechanism of sex steroid signaling in molluscs, we have, therefore, tried to isolate molluscan estrogen receptors from the prosobranch mollusc Thais clavigera. Cerebral ganglia of T. clavigera (Mollusca, Gastropoda, Prosobranchia) were subjected to RNA extraction, and degenerate primers for amino acid sequences conserved in vertebrate estrogen receptors were designed. PCR amplification using cerebral RNA and degenerate primers followed by 5'- and 3'-RACE identified the cDNA encoding T. clavigera estrogen receptor 1 (tcER1). The deduced amino acid sequence showed 93% identity in the DNA-binding domain and 72% identity in the ligand binding domain when compared to Aplysia estrogen receptor. Reporter gene assay revealed that tcER1 is constitutively active and unresponsive to estrogen. Quantitative analysis of the tcER1 mRNA level demonstrated the preferential expression in the ovary. Furthermore, cerebral ganglia expressed tcER1 at a high level in the spring followed by subsequent enlargement of the ovary in later seasons. These results suggest importance of tcER1 in the seasonal development of reproductive organs in T. clavigera.
authors.affiliation: Laboratory of Environmental Molecular Physiology, School of Life Science, Tokyo University of Pharmacy and Life Science, Hachioji, Tokyo 192-0392, Japan.
authors.forename: Masaaki
authors.initials: M
authors.lastname: Kajiwara
authors.forename: Shigehiro
authors.initials: S
authors.lastname: Kuraku
authors.forename: Takako
authors.initials: T
authors.lastname: Kurokawa
authors.forename: Kenichi
authors.initials: K
authors.lastname: Kato
authors.forename: Shingo
authors.initials: S
authors.lastname: Toda
authors.forename: Hidenori
authors.initials: H
authors.lastname: Hirose
authors.forename: Shigeru
authors.initials: S
authors.lastname: Takahashi
authors.forename: Yasuyuki
authors.initials: Y
authors.lastname: Shibata
authors.forename: Taisen
authors.initials: T
authors.lastname: Iguchi
authors.forename: Toshie
authors.initials: T
authors.lastname: Matsumoto
authors.forename: Takashi
authors.initials: T
authors.lastname: Miyata
authors.forename: Takashi
authors.initials: T
authors.lastname: Miura
authors.forename: Yuji
authors.initials: Y
authors.lastname: Takahashi
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001048:Aplysia / Q000235:genetics / Q000378:metabolism; D001483:Base Sequence; D019556:COS Cells; D002522:Chlorocebus aethiops; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000302:isolation & purification; D005260:Female; D015870:Gene Expression; D014644:Genetic Variation; D008297:Male; D008969:Molecular Sequence Data; D009928:Organ Specificity; D017434:Protein Structure, Tertiary; D011869:Radioligand Assay; D011960:Receptors, Estrogen / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism / Q000502:physiology; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D012908:Snails / Q000235:genetics* / Q000378:metabolism / Q000502:physiology; D014162:Transfection
chemical_list: D018076:DNA, Complementary; D011960:Receptors, Estrogen; D011993:Recombinant Fusion Proteins