| Autor: |
Hozumi, Katsuto, Kobori, Akiko, Sato, Takehito, Nishimura, Takashi, Habu, Sonoko |
| Zdroj: |
International Immunology; Oct1996, Vol. 8 Issue 10, p1473-1481, 9p |
| Abstrakt: |
In order to determine whether the cells immigrating into the thymus have been committed to the T cell lineage, we examined the gene expression of the TCR complex in fetal thymus (FT) and fetal liver (FL) precursors. We previously showed that c-kit bright-positive, Pgp-1 bright-positive and lineage markers negative fetal thymocytes (c-kit+ FT cells) are the most immature cells which do not undergo gene rearrangement of the TCR β chain. In this study, we demonstrated that the gene rearrangement of TCR γ as well as β chains does not occur in c-kit+ FT cells, but that the germline transcript of their TCR β was found in J-C regions. The TCR β gene was demethylated in c-kit+ FT cells. CD3 γ, δ and ɛ subunit genes were also expressed at the mRNA levels in c-kit+ FT cells, but cytoplasmic protein staining divided them into two populations: cytoplasmic CD3 ɛ positive and negative cells. These features were not observed in c-kit+ FL cells. Moreover, Ly-1 expression was found on c-kit+ FT cells but not on c-kit+ FL cells. These results indicate that DNA alteration on the TCR β gene initiates with other phenotype expression determining the T cell lineage in the thymus prior to TCR gene rearrangement. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
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