The protein SWAP-70 was isolated as part of a DNA recombination complex in
B lymphocytes, where it is predominantly expressed. In resting B cells, SWA
P-70 is found in the cytoplasm; upon B-cell activation, it is transported b
oth into the nucleus and to the cell membrane, where it is associated with
the B-cell receptor complex and may play a role in signal transduction. In
the nucleus, its involvement in heavy-chain class switch recombination has
been suggested. In this report, using restriction fragment length polymorph
ism, simple sequence length polymorphism, and fluorescence in situ hybridiz
ation, we map the chromosomal localization of the mouse and the human genes
to syntenic regions of mouse mid Chromosome (Chr) 7 and human Chr 11p15.