Integration of the transposon-like element ETn upstream of V lambda 2 in the cell line P3X63Ag8.

The cell line P3X63Ag8 and hybridomas obtained with it contain two rearranged V lambda 2 EcoRI fragments--6.8 kb and 7.4 kb in size. Southern blot analysis, molecular cloning, and mapping revealed that the rearrangements are related to one another and are not due to normal VJ joining. Sequence analysis indicated that the rearrangement was due to the integration of the transposon like element ETn upstream of V lambda 2. Because a normal embryonic V lambda 2 is still retained in this cell line one of the rearranged fragments must be due to a secondary event after the aneuploidization of the plasmacytoma. RNA dot blot analysis showed that the transposon is strongly expressed not only in embryonic cells but also in plasmacytomas, B lymphomas and T cell lines.