| Co-Investigator(Kenkyū-buntansha) |
GUNJI Yuji Jichi Medical School.Assistant Professor, 医学部, 講師 (90245043)
HATAKE Kiyohiko Jichi Medical School, Associate Professor, 医学部, 助教授 (80192699)
SHIMIZU Ritsuko Jichi Medical School, Instructor, 医学部, 助手 (40226262)
IMAGAWA Shigehiko Jichi Medical School, Assistant Professor, 医学部, 講師 (60231164)
KOMATSU Norio Jichi Medical School, Assistant Professor, 医学部, 講師 (50186798)
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| Research Abstract |
1) Lineage- c-kit+ Sca-1+ cells collected from normal mouse bone marrow (BM) cells contain most primitive hemopoietic stem cells, containing one hemopoietic progenitor cell from 2 cells, whereas 100 cells could rescue lethally irradiated mice.
2) Human CD34+, c-kit + CD33 + cells were maintained their colony forming ability when cultured on a feeder layr derived from normal human BM cells beyond 6 weeks. Human umbilical cord blood cells taken from abortive delivery contained more primitive stem cells than those from full term delivery.
3) From a megakaryocytic cell line UT-7, we established an erythropoietin (EP) dependent subclone, which expressed abundant EP receptors EPR.EP tyrosine-phosphorylated various kinase proteins, among which phospholipase-Cgamma1 was phosphorylate, suggesting that inositol phospholipid pathway was also activated with EP.We also established a thrombopoietin (mpl-ligand, TP) dependent cell line, and differentiation of erythropoiesis and thrombopoiesis will be studied more in detail.
4) There are two types of EPR in normal erythroid cells, a full length (F) type and a truncated (T) type. F type prevents apotosis under the low concentration of EP,while T type does not. we suggested the role of c-jun oncogene along with the prevention of apoptosis.
5) We found that immature human stem cells did not express Fas, an apotosis related gene, while mature hemopoietic cells did. We are investigating the role of Fas in the myeloid hemopoiesis.
6) Hep3B cells, established from human hepatoma, produce EP under anoxic condition. In EP gene there is a CACCC element -60bp upstream from CAP-site, and GATA element -30kb upstream of CAP-site. Using antisense against either sequence, we found that the former serves as a positive regulatory element while the latter is a negative regulator element. We also found that in the nuclear extracts binding specifically to these elements.
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