Overusage of Mouse DH Gene Segment, DFL16.1, IsStrain-Dependent and Determined bycis-Acting Elements

摘要

The DJH structure is of particular importance for diversity in the immunoglobulin heavychain because it encodes most of CDR3. Here, we investigate mechanisms responsible forgenerating the DJH structure. We found DFL16.1 was used at a high frequency in normaland transformed pre-B cells (fetal liver > 50%, A-MuLV lines ? 25%). One DFL16.1JH1structure was found repeatedly and was also present in DJH and VDJH databases,suggesting this structure may be conserved in the primary repertoire. Genetic analysisdemonstrated that C57BL/6 mice use DFL16.1 in DJH structures more frequently thanBALB/c. Examination of individual alleles in (C57BL/6 BALB/c)F1 A-MuLV cell linesrevealed that the C57BL/6-derived allele used DFL16.1 twice as often as the BALB/c. Thisresult indicates that part of the mechanism ensuring overusage of DFL16.1 gene segmentsiscis-acting.