FIG. 1.

Schematic of Alu-PCR. Human genomic DNA from CMVβ-gal-transduced cells was amplified by using the first set of primers: Alu5, an Alu-specific primer containing a tag; and C1, a CMV-specific primer. After an initial 10 cycles of PCR, the first set of primers was destroyed by uracil DNA glycosylase-induced nicks at dUTP (filled box). cTag5 (open box) represents a sequence complementary to the tag sequence on the newly synthesized strand. These PCR products were further amplified by using an internal primer, C2, for the CMV sequence plus TagA5, containing 16 nucleotides of Tag sequence and 6 nucleotides of Alu5 sequence. C3 was used as a specific CMV oligonucleotide probe for Southern hybridization. C4 and TagA5 were used to further amplify the above Alu-PCR products in order to obtain discrete bands for direct sequencing.