Abstract
Variable (V) genes of immunoglobulins undergo somatic hypermutation by activationinduced deaminase (AID) to generate amino acid substitutions that encode antibodies with increased affinity for antigen. Hypermutation is restricted to germinal center B cells and cannot be recapitulated in ex vivo-activated splenic cells, even though the latter express high levels of AID. This suggests that there is a specific feature of antigen activation in germinal centers that recruits AID to V genes which is absent in mitogen-activated cultured cells. Using two Igh knock-in mouse models, we found that RNA polymerase II accumulates in V regions in B cells after both types of stimulation for an extended distance of 1.2 kb from the TATA box. The paused polymerases generate abundant single-strand DNA targets for AID. However, there is a distinct accumulation of the initiating form of polymerase, along with the transcription cofactor Spt5 and AID, in the V region from germinal center cells, which is totally absent in cultured cells. These data support a model where mutations are prevalent in germinal center cells, but not in ex vivo cells, because the initiating form of polymerase is retained, which affects Spt5 and AID recruitment.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 2297-2306 |
| Number of pages | 10 |
| Journal | Journal of Experimental Medicine |
| Volume | 211 |
| Issue number | 11 |
| DOIs | |
| State | Published - 2014 |
| Externally published | Yes |
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ASJC Scopus subject areas
- Immunology
- Immunology and Allergy
- Medicine(all)
Cite this
Spt5 accumulation at variable genes distinguishes somatic hypermutation in germinal center B cells from ex vivo-activated cells. / Maul, Robert W.; Cao, Zheng; Venkataraman, Lakshmi; Giorgetti, Carol A.; Press, Joan L.; Denizot, Yves; Du, Hansen; Sen, Ranjan; Gearhart, Patricia J.
In: Journal of Experimental Medicine, Vol. 211, No. 11, 2014, p. 2297-2306.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Spt5 accumulation at variable genes distinguishes somatic hypermutation in germinal center B cells from ex vivo-activated cells
AU - Maul, Robert W.
AU - Cao, Zheng
AU - Venkataraman, Lakshmi
AU - Giorgetti, Carol A.
AU - Press, Joan L.
AU - Denizot, Yves
AU - Du, Hansen
AU - Sen, Ranjan
AU - Gearhart, Patricia J.
PY - 2014
Y1 - 2014
N2 - Variable (V) genes of immunoglobulins undergo somatic hypermutation by activationinduced deaminase (AID) to generate amino acid substitutions that encode antibodies with increased affinity for antigen. Hypermutation is restricted to germinal center B cells and cannot be recapitulated in ex vivo-activated splenic cells, even though the latter express high levels of AID. This suggests that there is a specific feature of antigen activation in germinal centers that recruits AID to V genes which is absent in mitogen-activated cultured cells. Using two Igh knock-in mouse models, we found that RNA polymerase II accumulates in V regions in B cells after both types of stimulation for an extended distance of 1.2 kb from the TATA box. The paused polymerases generate abundant single-strand DNA targets for AID. However, there is a distinct accumulation of the initiating form of polymerase, along with the transcription cofactor Spt5 and AID, in the V region from germinal center cells, which is totally absent in cultured cells. These data support a model where mutations are prevalent in germinal center cells, but not in ex vivo cells, because the initiating form of polymerase is retained, which affects Spt5 and AID recruitment.
AB - Variable (V) genes of immunoglobulins undergo somatic hypermutation by activationinduced deaminase (AID) to generate amino acid substitutions that encode antibodies with increased affinity for antigen. Hypermutation is restricted to germinal center B cells and cannot be recapitulated in ex vivo-activated splenic cells, even though the latter express high levels of AID. This suggests that there is a specific feature of antigen activation in germinal centers that recruits AID to V genes which is absent in mitogen-activated cultured cells. Using two Igh knock-in mouse models, we found that RNA polymerase II accumulates in V regions in B cells after both types of stimulation for an extended distance of 1.2 kb from the TATA box. The paused polymerases generate abundant single-strand DNA targets for AID. However, there is a distinct accumulation of the initiating form of polymerase, along with the transcription cofactor Spt5 and AID, in the V region from germinal center cells, which is totally absent in cultured cells. These data support a model where mutations are prevalent in germinal center cells, but not in ex vivo cells, because the initiating form of polymerase is retained, which affects Spt5 and AID recruitment.
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UR - http://www.scopus.com/inward/citedby.url?scp=84908253754&partnerID=8YFLogxK
U2 - 10.1084/jem.20131512
DO - 10.1084/jem.20131512
M3 - Article
C2 - 25288395
AN - SCOPUS:84908253754
VL - 211
SP - 2297
EP - 2306
JO - Journal of Experimental Medicine
JF - Journal of Experimental Medicine
SN - 0022-1007
IS - 11
ER -