| Co-Investigator(Kenkyū-buntansha) |
NISHIHARA Masugi The University of Tokyo, Graduate School of Agricultural and Life Science, Assoc, 大学院・農学生命科学研究科, 助教授 (90145673)
MORI Yuji The University of Tokyo, Graduate School of Agricultural and Life Science, Profe, 大学院・農学生命科学研究科, 教授 (40157871)
MURAKAMI Noboru University of Miyazaki, Department of Agriculture Associate Professor, 農学部, 助教授 (80150192)
ITAGAKI Shin-ichi The University of Tokyo, Graduate School of Agricultural and Life Science, Assoc, 大学院・農学生命科学研究科, 助教授 (00159823)
OGAWA Tomoya The University of Tokyo, Graduate School of Agricultural and Life Science, Profe, 大学院・農学生命科学研究科, 教授 (30087572)
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| Research Abstract |
Development of various organs begins immediately after initiation of placentation. We previously showed that rat amniotic fluid contains immunoreactive placental lactogen-like molecules with different molecular sizes and pI values from the authentic placental lactogens (PLs) in the rat. In the present study, immunoreactive PLs residing in the amniotic fluid were characterized further by two-dimensional SDS gel electrophoresis and we confirmed that amniotic fluid collected from rats on day 12 of pregnancy contains two PL-like molecules, tentatively called A1 (MW 75 kDa, pI4.6) and A2 (MW 99-102 kDa, pI 5.3-5.4). PLs have ability to bind to prolactin (PRL) receptor and one of the target tissues for PLs is the brain in adult animals. Therefore, we tried to detect PRL receptor (PRL-R) mRNAs in fetal rat brains, and the gene expression is detected very early in developing fetal brain. To evaluate a role for N-linked oligosaccharides in the molecular action of rat placental lactogen-I mosaic
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(PL-Im), recombinant PL-Im (recPL-Im) and three recPL-Im mutants were produced in COS7 cells. It became evident that PL-Im was N-glycosylated at both Asn79 and Asn128. In addition, the two N-linked oligosaccharides which are involved in its biological activity. Interestingly, the ability of PL-Im to bind PRL-R and activate JAK2 appears to be independent of the N-glycosylation. We also found a novel gene, 4P16, which is related to the proliferation of neural cells. The gene expression is also stimulated by PL-Im in the Nb2 cell line. With the aim of identifying molecules that are expressed specifically in the brain during neurogenesis, we tried to generate monoclonal antibodies which recognize molecules showing unique temporal expression patterns and molecular characteristics. One of the antibodies, Mab3C8, recognized a 100-kDa antigen that is enriched in fetal brain. This 100-kDa antigen was constantly expressed during fetal life (from E12 to E20) and became undetectable two days after birth. The molecule unique to the fetal brain, an O-linked sialoglycoprotein with a molecular weight of 100 kDa (FOG100), was found by generating an antibody. In addition to these results, we also found that the fetal brain express the mRNAs for tree orphan receptors, NGFI-B,Rev-erbAa, Rev-erbAb. Finally, we have idenstified several forms of G protein beta sabunit with different PI values in the placenta and brain. Less
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