TY - JOUR
T1 - Switch recombination breakpoints are strictly correlated with DNA recognition motifs for immunoglobulin Sγ3 DNA-binding proteins
AU - Wuerffel, Robert
AU - Jamieson, Christina E.
AU - Morgan, Leslie
AU - Merkulov, Gennady V.
AU - Sen, Ranjan
AU - Kenter, Amy L.
PY - 1992/8/1
Y1 - 1992/8/1
N2 - The deletion looping out model of switch (S) recombination predicts that the intervening DNA between switch regions will be excised as a circle. Circular excision products of immunoglobulin switch recombination have been recently isolated from lipopolysaccharide (LPS)-stimulated spleen cells. The recombination breakpoints in these large circles were found to fall within switch regions. Since switch recombination is clearly focused on switch regions, we hypothesized that some DNA-binding protein factor might be involved in specifically recognizing and facilitating the alignment of switch regions before recombination. Two DNA-binding proteins that specifically interact with two discrete regions of the Sγ3 tandem repeat have been identified in crude and partially purified nuclear extracts derived from LPS- and dextran sulfate (DxS)-activated splenic B cells. The first factor has been found indistinguishable from NF-κB by mobility shift assays, methylation interference, competition binding studies, and supershift analysis using an antiserum specific for the p50 component. The second appears to be composed of two closely traveling mobilities that do not separate upon partial purification. This second complex is unique and specific for Sγ3 by methylation interference assays and competition-binding analysis. The sites at which recombination occurs in the Sγ3 switch region have been analyzed and found to strictly correlate with the binding sites of the Sγ3 switch binding proteins.
AB - The deletion looping out model of switch (S) recombination predicts that the intervening DNA between switch regions will be excised as a circle. Circular excision products of immunoglobulin switch recombination have been recently isolated from lipopolysaccharide (LPS)-stimulated spleen cells. The recombination breakpoints in these large circles were found to fall within switch regions. Since switch recombination is clearly focused on switch regions, we hypothesized that some DNA-binding protein factor might be involved in specifically recognizing and facilitating the alignment of switch regions before recombination. Two DNA-binding proteins that specifically interact with two discrete regions of the Sγ3 tandem repeat have been identified in crude and partially purified nuclear extracts derived from LPS- and dextran sulfate (DxS)-activated splenic B cells. The first factor has been found indistinguishable from NF-κB by mobility shift assays, methylation interference, competition binding studies, and supershift analysis using an antiserum specific for the p50 component. The second appears to be composed of two closely traveling mobilities that do not separate upon partial purification. This second complex is unique and specific for Sγ3 by methylation interference assays and competition-binding analysis. The sites at which recombination occurs in the Sγ3 switch region have been analyzed and found to strictly correlate with the binding sites of the Sγ3 switch binding proteins.
UR - http://www.scopus.com/inward/record.url?scp=0026770992&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0026770992&partnerID=8YFLogxK
M3 - Article
C2 - 1500850
AN - SCOPUS:0026770992
SN - 0022-1007
VL - 176
SP - 339
EP - 349
JO - Journal of Experimental Medicine
JF - Journal of Experimental Medicine
IS - 2
ER -