IgH locus rearrangements in pre– and pro–B-cell subsets from Eμ-A1 transgenic mice.

DNA from IgM⁻B220⁺CD43⁺ and IgM⁻B220⁺CD43⁻ bone marrow populations purified by cell sorting was amplified using PCR for DJ and V(D)J rearrangements under semiquantitative conditions. Southern blots of PCR products were hybridized with internal oligonucleotide probes (see “Materials and methods”). Parallel amplification of CD14 served as a control and was assessed by ethidium bromide staining.