Chromosomal position of a VH gene segment determines its activation and inactivation as a substrate for V(D)J recombination.
Complete IgHC gene rearrangement occurs only in B cells in a stage-specific and ordered manner. We used gene targeting to reposition a distal V(H) gene segment to a region just 5' of the D(H) gene cluster and found its activation to be highly dependent on the chromosomal domain within which it resides. The targeted V(H) gene segment rearranged at a higher frequency than its endogenous counterpart, its rearrangement was no longer ordered, and its ability to be silenced by allelic exclusion was lost. Additionally, the targeted V(H) gene segment lost lineage specificity, as VDJ(H) rearrangement was observed in thymocytes. These data suggest that locus contraction, mimicked by proximal targeting, can override any regulation imposed by DNA sequences immediately surrounding V(H) gene segments.
Division of Immunology, Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA.
Jamie Geier
JG
Bates
Dragana
D
Cado
Hector
H
Nolla
Mark S
MS
Schlissel
D000483:Alleles; D000818:Animals; D001402:B-Lymphocytes / Q000378:metabolism; D019070:Cell Lineage; D002874:Chromosome Mapping; D002875:Chromosomes; D015321:Gene Rearrangement; D005803:Genes, Immunoglobulin / Q000235:genetics*; D007143:Immunoglobulin Heavy Chains / Q000235:genetics*; D051379:Mice; D008822:Mice, Transgenic; D008957:Models, Genetic; D015398:Signal Transduction; D013950:Thymus Gland / Q000378:metabolism; D045567:VDJ Recombinases / Q000235:genetics*
D007143:Immunoglobulin Heavy Chains; D045567:VDJ Recombinases