Nucleic Acids Research, 1987, Vol. 15, No. 1 1-14
© 1987
Articles |
Reciprocal recombination products of VK-JK joining reactions in human lymphoid cell lines
Institut für Physiologische Chemie, Physikalische Biochemie und Zellbiologie der Universität München, FRG
Received November 3, 1986. Accepted December 10, 1986.
The recombination process that joins a VK to a JK segment of an immunoglobulin gene generates a second, reciprocal recombination product called f fragment. In this second product the regions flanking the VK and JK segments in the germline are joined in a head to head fashion. We now analysed f fragments in the human lymphoid cell lines Daudi, JI and IARC/BL41. All three f fragments contain JK1 flanks; the VK derived moiety of f Daudi and f41 could be traced back to known germline VK genes. There is a precise head to head joining of the heptanucleotide signal sequences in f Daudi and fJI while in f41 six nucleotides are present between the signal sequences. In contrast to the VK-JK recombination products, the f fragments were found to lack somatic mutations. The structures of the f fragments are discussed in the context of the VK-JK rearrangement mechanism.