The T cell receptor beta enhancer promotes access and pairing of Dbeta and Jbeta gene segments during V(D)J recombination.
The precise function of cis elements in regulating V(D)J recombination is still controversial. Here, we determined the effect of inactivation of the TCRbeta enhancer (Ebeta) on cleavage and rearrangement of Dbeta1, Dbeta2, Jbeta1, and Jbeta2 gene segments in CD4-CD8- [double-negative (DN)] and CD4+CD8+ [double-positive (DP)] thymocytes. In Ebeta-deficient mice, (i) Dbeta1 rearrangements were more severely impaired than Dbeta2 rearrangements; (ii) most of the Dbeta and Jbeta cleavages and rearrangements occurred in DP, rather than in DN, thymocytes; and (iii) most of the 3' Dbeta1 cleavages were coupled to 5' Dbeta2 cleavages instead of to Jbeta cleavages, resulting in nonstandard Dbeta1-Dbeta2-Jbeta2 joints. These findings suggest that the Ebeta regulates TCRbeta rearrangement by promoting accessibility of Dbeta and Jbeta gene segments in DN thymocytes and proper pairing between Dbeta1 and Jbeta gene segments for cleavage and joining in DP thymocytes.
Center for Cancer Research and Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
Chun Jeih
CJ
Ryu
Brian B
BB
Haines
Dobrin D
DD
Draganov
Yun Hee
YH
Kang
Charles E
CE
Whitehurst
Tara
T
Schmidt
Hyo Jeong
HJ
Hong
Jianzhu
J
Chen
D000818:Animals; D001483:Base Sequence; D015139:Blotting, Southern; D015704:CD4 Antigens / Q000096:biosynthesis; D016827:CD8 Antigens / Q000096:biosynthesis; D004742:Enhancer Elements, Genetic; D015321:Gene Rearrangement; D019674:Genes, T-Cell Receptor beta / Q000235:genetics*; D005822:Genetic Vectors; D051379:Mice; D008957:Models, Genetic; D008969:Molecular Sequence Data; D009154:Mutation; D016133:Polymerase Chain Reaction; D011995:Recombination, Genetic; D013950:Thymus Gland / Q000166:cytology / Q000378:metabolism; D045567:VDJ Recombinases / Q000235:genetics* / Q000378:metabolism
D015704:CD4 Antigens; D016827:CD8 Antigens; D045567:VDJ Recombinases