2005 Fiscal Year Final Research Report Summary
Identification of factors for ES cell function
| Project/Area Number |
16606001
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
幹細胞生物学
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| Research Institution | The University of Tokyo |
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Principal Investigator |
SATO Mitsuharu The University of Tokyo, Institute for Medical Science, Research associate, 医科学研究所, 助手 (40332621)
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| Co-Investigator(Kenkyū-buntansha) |
YOSHIDA Nobuaki The University of Tokyo, Institute for Medical Science, Professor, 医科学研究所, 教授 (10250341)
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| Project Period (FY) |
2004 – 2005
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| Keywords | embryonic stem cells / multi-potency / Rex-1 / PTB / Rod-1 / gene targeting / cell differentiation |
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| Research Abstract |
We focused on a regulatory region of Rex-1 gene to identify the factor responsible for ES cell gene regulation. Using protein purification and DNA-binding assay, we found polypyrimidine tract binding-factor (PTB) binds to the region. Although PTB was originally identified as an RNA binding protein, we showed it binds to pyrimidine rich sequence within Rex-1 or Nanog promoters.
We generated PTB deficient mice and found that PTB null embryo was lethal at the stage of implantation. To investigate the importance of PTB in ES cell function, we disrupted both of alleles of PTB gene in ES cells. PTB null ES cells showed severe defect in cell proliferation and several differentiation markers were not induced in PTB null ES cells. The defect in cell proliferation was rescued when PTB expression vector was introduced in PTB null cells.
As retinoic acid induced cell differentiation did not alter the expression level of PTB, we assumed that other ES cell specific factors were coupled with PTB in ES cells. Alternatively, ES cell specific modification could be occur on PTB. In screening for PTB binding protein, we found that Rod-1 was associated with PTB in ES cells. PTB and Rod-1 are highly homologous in amino acid sequence, but Rod-1 could not rescue the phenotype of PTB null ES cells. We started generating Rod-1 deficient ES cell lines to test whether Rod-1 was required for PTB to function.
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