TY - JOUR
T1 - VprBP (DCAF1) regulates RAG1 expression independently of dicer by mediating RAG1 degradation
AU - Max Schabla, N.
AU - Perry, Greg A.
AU - Palmer, Victoria L.
AU - Swanson, Patrick C.
N1 - Funding Information:
This work was supported by National Institutes of Health (NIH) Grant R01GM102487 (to P.C.S.) and by revenue from Nebraska’s excise tax on cigarettes awarded to Creighton University through the Nebraska Department of Health & Human Services. NIH funding to support research laboratory construction (Grant C06 RR17417-01), the Creighton University Animal Resource Facility (Grant G20RR024001), the acquisition of the GE Healthcare Typhoon 9410 Variable Mode Imager (Grant S10RR027352), and the Bio-Rad ZE5 Cell Analyzer (Grant 3R01GM102487-03S1) is gratefully acknowledged.
Funding Information:
This work was supported by National Institutes of Health (NIH) Grant R01GM102487 (to P.C.S.) and by revenue from Nebraska's excise tax on cigarettes awarded to Creighton University through the Nebraska Department of Health & Human Services. NIH funding to support research laboratory construction (Grant C06 RR17417-01), the Creighton University Animal Resource Facility (Grant G20RR024001), the acquisition of the GE Healthcare Typhoon 9410 Variable Mode Imager (Grant S10RR027352), and the Bio-Rad ZE5 Cell Analyzer (Grant 3R01GM102487-03S1) is gratefully acknowledged.
Publisher Copyright:
© 2018 American Association of Immunologists. All rights reserved.
PY - 2018/8/1
Y1 - 2018/8/1
N2 - The assembly of Ig genes in developing B lymphocytes by V(D)J recombination is initiated by the RAG1-RAG2 endonuclease complex. We previously identified an interaction between RAG1 and viral protein R binding protein (VprBP) (also known as DNA damage binding protein 1 cullin 4-associated factor 1 [DCAF1]), a substrate receptor for the cullin 4-really interesting new gene (RING) E3 ubiquitin ligase (CRL4). We report in this article that in mice, B cell-intrinsic loss of VprBP increases RAG1 protein levels and disrupts expression of the endoribonuclease Dicer, which is essential for microRNA maturation. Rag1/2 transcription is known to be derepressed by loss of microRNA-mediated suppression of phosphatase and tensin homolog, raising the possibility that the elevated level of RAG1 observed in VprBP-deficient B cells is caused indirectly by the loss of Dicer. However, we show that VprBP restrains RAG1 expression posttranscriptionally and independently of Dicer. Specifically, loss of VprBP stabilizes RAG1 protein, which we show is normally degraded via a mechanism requiring both 20S proteasome and cullin-RING E3 ubiquitin ligase activity. Furthermore, we show that RAG1 stabilization through small molecule inhibition of cullin-RING E3 ubiquitin ligase activation promotes V(D)J recombination in a murine pre-B cell line. Thus, in addition to identifying a role for VprBP in maintaining Dicer levels in B cells, our findings reveal the basis for RAG1 turnover and provide evidence that the CRL4VprBP(DCAF1) complex functions to maintain physiological levels of V(D)J recombination.
AB - The assembly of Ig genes in developing B lymphocytes by V(D)J recombination is initiated by the RAG1-RAG2 endonuclease complex. We previously identified an interaction between RAG1 and viral protein R binding protein (VprBP) (also known as DNA damage binding protein 1 cullin 4-associated factor 1 [DCAF1]), a substrate receptor for the cullin 4-really interesting new gene (RING) E3 ubiquitin ligase (CRL4). We report in this article that in mice, B cell-intrinsic loss of VprBP increases RAG1 protein levels and disrupts expression of the endoribonuclease Dicer, which is essential for microRNA maturation. Rag1/2 transcription is known to be derepressed by loss of microRNA-mediated suppression of phosphatase and tensin homolog, raising the possibility that the elevated level of RAG1 observed in VprBP-deficient B cells is caused indirectly by the loss of Dicer. However, we show that VprBP restrains RAG1 expression posttranscriptionally and independently of Dicer. Specifically, loss of VprBP stabilizes RAG1 protein, which we show is normally degraded via a mechanism requiring both 20S proteasome and cullin-RING E3 ubiquitin ligase activity. Furthermore, we show that RAG1 stabilization through small molecule inhibition of cullin-RING E3 ubiquitin ligase activation promotes V(D)J recombination in a murine pre-B cell line. Thus, in addition to identifying a role for VprBP in maintaining Dicer levels in B cells, our findings reveal the basis for RAG1 turnover and provide evidence that the CRL4VprBP(DCAF1) complex functions to maintain physiological levels of V(D)J recombination.
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U2 - 10.4049/jimmunol.1800054
DO - 10.4049/jimmunol.1800054
M3 - Article
C2 - 29925675
AN - SCOPUS:85050765075
VL - 201
SP - 930
EP - 939
JO - Journal of Immunology
JF - Journal of Immunology
SN - 0022-1767
IS - 3
ER -