FIG. 1.

Southern blot of PCR amplification spanning the SCR1 region of the common marmoset (Callithrix jacchus). The brain, heart, liver, lung, kidney, small intestine, spleen, and stomach of a common marmoset were isolated and homogenized in TRIzol, mRNA was extracted, and cDNA was prepared with RT. PCR was performed across the SCR1 region with oligonucleotide primers derived from the conserved signal peptide and SCR3 domains. A 300-bp product was indicative of a deleted SCR1 domain, while a 522-bp product was produced from a complete copy of the CD46 cDNA. Most organs from the marmoset contained the deleted form of CD46, but the brain and heart may contain small amounts of the undeleted species in addition to the major deleted mRNA. B95-8 marmoset B cells were homogenized, and mRNA was extracted and treated in a similar manner to that from the marmoset organs. Undeleted and deleted forms of CD46 were present in the B95-8 cells. PCR analysis was also performed on cDNA clones which had been prepared from mRNA isolated from B95-8 cells and inserted into the pCR Script AMP (SK+) vector. The PCR products from the deleted clone (CD46ΔSCR1) and the nondeleted clone (CD46) templates were also analyzed. PCR products were resolved by agarose gel electrophoresis, transferred to nitrocellulose, probed with ³²P-labelled fragments derived from the SCR2 and SCR3 regions of CD46, and subjected to autoradiography with Royal X-OMAT film for 24 h.