Competitive RT-PCR analysis of hematopoietic cell lines for differential expression of D-type cyclins. The indicated B-cell lines (upper part), T-cell lines (middle part), and myeloid cell lines (lower part) at log phase were subjected to RNA extraction and competitive RT-PCR. PCR products were separated on an agarose gel containing ethidium bromide and photographed. Arrows indicate PCR products corresponding to cyclins D1, D2, and D3. MEG01s cells served as size markers. *t ( 11; 14 ) ( q13; q32 ) - bearing cell lines; **HTLV-1–infected cell lines.