Quantitative analysis of integrated Eα;d gene expression in C57BL/6 transgenic mice.

We performed quantitative analysis of E_α^d gene expression in the transgenic mice, created by microinjecting cloned E_α^d gene fragments into C57BL/6 fertilized eggs. DNA dot-blot analysis revealed that E_α^d gene-introduced transgenic mice (B6E_α^d transgenic mice) contain 20 copies per cell of the E_α^d gene in their genome. RNA dot-blot analysis revealed that the amount of E_α^d mRNAs in B6E_α^d transgenic spleen cells is 20-40-fold higher than those in normal BALB/c or (BALB × C578L/6)F₁ (CEF₁) spleen cells. However, the amount of E_α^d molecules expressed on B6E_α^d transgenic spleen cells was similar to that expressed on normal BALB/c of CBF₁, spleen cells on a gene-dose basis. The amount of endogenous E_α^d mRNA in the B6E_α^d transgenic spleen cells was almost equal to that of normal B6 spleen cells. Since the cell surface I-E molecule is formed by non-covalent association of E. and E_&beta chain, these results suggest that, in spite of the high expression of integrated E_α^d gene in the cytoplasm of B6E_α^d transgenic mice, the amount of E_α^d gene expression on the cell surface is limited by the amount of endogenous E_α^d gene products. [ABSTRACT FROM AUTHOR]