Start of mu-chain production by the further two-step rearrangements of immunoglobulin heavy chain genes on one chromosome from a DJH/DJH configuration in an Abelson virus-transformed cell line: evidence of secondary DJH complex formation.

A variant was selected from an Abelson virus-transformed cell line with identifiable and distinguishable DJH rearrangements on both chromosomes. Southern blotting experiments suggested that this variant resulted from a secondary DJH complex formation accompanied with the deletion of one of the DJH rearrangements on the same chromosome. Furthermore, this variant started making mu-chains by the further functional join of a VH gene to the secondarily formed DJH complex. Thus, we describe here the first evidence of a secondary DJH complex formation.