Fig. 3.

Semiquantitative comparison of the mRNA splice variants of the human MCP (CD46) gene (a) and the tissue-specific expression of the protein isoforms (b) in lung and kidney of the three transgenic mouse strains. Total protein and RNA fractions were isolated from snap frozen lung and kidney tissue of male and female animals of all three mouse strains (MY II, hCD46Ge and UAB), from Jurkat cells and from CHO cells transfected with cDNAs coding for the BC1, C1, BC2 or C2 isoform. For RNA analyses, 1 μg was used to perform RT-PCRs (a). For PCR amplification, primers annealing to CCP 4 and the 3′ (untranslated region of MCP (CD46) were used (see Materials and methods). For protein analyses 10 μg of total protein extract were separated by SDS-PAGE under nonreducing conditions and Western blotted with polyclonal anti-MCP (CD46) Ab (b). The slight differences in the M_r of the upper and lower MCP (CD46) protein forms (for example, between Jurkat and CHO cells) are commonly seen among various types of cells and reflect distinct branching patterns of the N-linked sugars [33].