RT-PCR analysis of expression of transcripts in the 12q21.33-12q22 region. Three B-cell preparations from healthy donors and the patient samples previously analyzed by Northern blotting were analyzed by RT-PCR using primers specific for the genes, ESTs, and CLLU1 transcripts shown in Figure 2 (for a list of primers and analyzed transcripts, see Table S1). The size marker is a 100-bp ladder, and the top band in all images corresponds to 800 bp.