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Akihiko Yamaguchi Last modified date:2018.10.15

Assistant Professor / Marine Bioresources
Department of Bioresource Sciences
Faculty of Agriculture


Graduate School
Undergraduate School


E-Mail
Homepage
http://www.agr.kyushu-u.ac.jp/lab/sui1/lmb.html
Fishes are interesting group of organisms in which to analyze sex determination and gonad development because they have various type of sexuality. Recently, the medaka Y-specific sex determination gene, DMY which is a duplicated copy of autosomal DMRT1 was identified. In other fishes, however, no molecular information exists about the mode of sex determination, sex chromosomes or the process of gonad differentiation. Our goal is determination of the common molecular mechanism of gonad development of useful marine fishes at the molecular and cellular level, then bring it back to the our life, enviroment and society.
Please step into the world of the marine reproductive biology with us. .
Academic Degree
Ph.D.
Field of Specialization
Reproductive Biology, Molecular Cell Biology
Outline Activities
Fishes are interesting group of organisms in which to analyze sex determination and gonad development because they have various type of sexuality. Recently, the medaka Y-specific sex determination gene, DMY which is a duplicated copy of autosomal DMRT1 was identified. In other fishes, however, no information exists about the mode of sex determination, sex chromosomes or the process of gonad differentiation. We study molecular mechanism of these process using kinds of fishes(goldfish, pufferfish, zebrafish, so on). Recently, we try to analyze the germ cell differntiation during early larvae of Japanese pufferfish, Takifugu rubripes which has the most compact genomes of all vertebrates and used as a good model for comparative genome analysis. At present, we have been investigating the transcription factors that are necesary for differentiation of germ cells. Aromatase is an important steroidogenic enzyme converts androgen to estroge.Brain type aromatase (CYP19B) has a unique characteristics because fish brain 100-1000 fold more proteins and activity than mammals. We have been studying the role of estrogen in fish brain as well as gonads and other somatic organs.
Research
Research Interests
  • The molecular study of gonadal sexual differntiation, development, maturationin and enviromental responsibility of Torafugu (Takifugu rubripes)
    keyword : Torafugu, gonadal sexual differntiation, transcription factor, steroidgenic enzyme, ER, GTH, Rhodopsin, opsin
    2000.10We analyze transcription factors, steroidogenic enzymes that works for sex-differentiation and development of the gonads. Recently, we target on the nuclear matrix that may be a key structure to understand molecular mechanism of gene expression system in germ cells..
  • Molecular analysis of nuclear (germinal vesicle) structure and function in fish oocytes
    keyword : lamin,protein kinase,MPF,cdc2,SR protein, oocyte maturation,goldfish
    2000.10.
Academic Activities
Papers
1. Akihiko Yamaguchi, Miho Iwatani, Mariko Ogawa, Hajime Kitano, Michiya Matsuyama, In vitro characterization of the RS motif in N-terminal head domain of goldfish germinal vesicle lamin B3 necessary for phosphorylation of the p34cdc2 target serine by SRPK1, FEBS Open Bio, 10.1016/j.fob.2013.03.003, 3, 165-176, 2013.03, The nuclear envelopes surrounding the oocyte germinal vesicles of lower vertebrates (fish and frog)
are supported by the lamina, which consists of the protein lamin B3 encoded by a gene found also in
birds but lost in the lineage leading to mammals. Like other members of the lamin family, goldfish
lamin B3 (gfLB3) contains two putative consensus phosphoacceptor p34cdc2 sites (Ser-28 and Ser-398)
for the M-phase kinase to regulate lamin polymerization on the N- and C-terminal regions flanking a
central rod domain. Partial phosphorylation of gfLB3 occurs on Ser-28 in the N-terminal head domain
in immature oocytes prior to germinal vesicle breakdown, which suggests continual rearrangement of
lamins by a novel lamin kinase in fish oocytes. We applied the expression-screening method to isolate
lamin kinases by using phosphorylation site Ser-28-specific monoclonal antibody and a vector encoding
substrate peptides from a goldfish ovarian cDNA library. As a result, SRPK1was screened as a prominent
lamin kinase candidate. The gfLB3 has a short stretch of the RS repeats (9-SRASTVRSSRRS-20) upstream
of the Ser-28, within the N-terminal head. This stretch of repeats is conserved among fish lamin B3 but
is not found in other lamins. In vitro phosphorylation studies and GST-pull down assay revealed that
SRPK1 bound to the region of sequential RS repeats (9–20) with affinity and recruited serine into the
active site by a grab-and-pull manner. These results indicate SRPK1may phosphorylate the p34cdc2 site
in the N-terminal head of GV-lamin B3 at the RS motifs,which have the general property of aggregation..
2. Yamaguchi, A., Katsu,Y., Matsuyama, M., Yoshikuni, M., Nagahama,Y., Phosphorylation of the p34cdc2 target site on goldfish germinal vesicle lamin B3 before oocyte maturation, European Journal of Cell Biology, 85, 501-517, 2006.06.
3. Yamaguchi, A., Lee,K-H., Fujimoto, H., kadomura,K., Yasumoto,S.,Matsuyama, M., Expression of DMRT gene and its roles in early gonadal development of Japanese pufferfish Takifugu rubripes, Comarative Biochemistry and Physiology Part D: Genomics and Proteomics, 1, 59-68, 2006.01.
4. Yamaguchi, A. and Nagahama, Y., Somatic lamins in germinal vesicles of goldfish (Carassius auratus) oocytes., Cell Struc. Func., 26, 693‐703., 2001.01.
5. Yamaguchi, A., Yamashita, M., Yoshikuni, M. and Nagahama, Y., Identification and molecular cloning of germinal vesicle lamin B3 in goldfish (Carassius autratus) oocytes., Eur. J. Biochem., 268, 932-939., 2001.01.
6. Yamaguchi, A., Yamashita, M., Yoshikuni, M., Hotta,Y., Nurse, P. and Nagahama, Y., Involvement in meiotic prophase of H1 kinase and p34cdc2 homologues in lily (Lilium longiflorum) microsporocytes., Develop. Growth Differ., 33, 625-632., 1991.01.
Membership in Academic Society
  • Zoological Society of Japan
Educational
Educational Activities
Basic Biology Experiment
Laboratory in Fisheries Biology I
Laboratory in Fisheries Biology II
Molecular Biology
Animal and Marine Life Science (G30 English program)