Allele primers, amplifies a 434 bp DNA fragment from SRA-deficient ZK1, ZK2 and ZK6 cells. With primers for MARCO wild-type allele, amplifies a 500 bp DNA fragment from WT mice; with primers for MARCO mutant allele, amplifies a 850 bp DNA fragment from ZK cells. ZK1, ZK2 and ZK6 clones exhibited both MARCO and SRA-I/II-deficient. PCR products, ca.10 l/each was resolved on a 1.5 agarose gel by gel