V(D)J recombination generates a high frequency of nonstandard TCR D[delta]-associated rearrangements in thymocytes
- Albany Medical College, NY (United States)
The standard products of V(D)J recombination are coding junctions, which encode Ag receptor polypeptide, and their commonly excised reciprocal products, signal junctions. Additional nonstandard products also have been detected, mostly in artificial recombination substrate studies. The occurrence of nonstandard products, including pseudonormal, hybrid, and open/shut junctions, indicates significant indeterminacy of the V(D)J recombinase. However, the incidence of nonstandard products of endogenous Ag receptor genes in vivo has not been specifically addressed. The data presented here show that for the TCR-[delta] locus, D element-associated recombination in mouse thymocytes results in a high incidence of nonstandard recombination products. D[delta]1-D[delta]2 rearrangements, both chromosome retained and excised episomal products, were studied by polymerase chain reaction amplification, cloning, and sequence analysis. The proximity of D[delta]1 and D[delta]2 elements, and the fact that both are flanked by 5[prime] and 3[prime] recombination signal sequences with 12-bp and 23-bp spacers, respectively, results in frequent pseudonormal joining. The resulting products are signal junctions retained on the chromosome. Excised episomal products include coding junctions, hybrid junctions formed in apparent violation of the 12/23 spacer rule, and standard signal junctions; some signal junctions show evidence of imprecise cleavage. Evidence for open/shut and/or oligonucleotide capture events was also seen. Similar rearrangements were detectable in thymocytes of mutant scid mice. These findings indicate a high degree of indeterminancy of V(D)J recombinase-mediated D[delta]1-D[delta]2 rearrangement in both wild-type and scid thymocytes. This indeterminacy affects the productive potential of TCR-[delta] loci. 45 refs., 4 figs.
- OSTI ID:
- 6448469
- Journal Information:
- Journal of Immunology; (United States), Vol. 150:6; ISSN 0022-1767
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
RECEPTORS
GENE RECOMBINATION
THYMOCYTES
DNA HYBRIDIZATION
DNA SEQUENCING
DNA-CLONING
LYMPHOCYTES
ANIMAL CELLS
BIOLOGICAL MATERIALS
BLOOD
BLOOD CELLS
BODY FLUIDS
CLONING
CONNECTIVE TISSUE CELLS
HYBRIDIZATION
LEUKOCYTES
MATERIALS
MEMBRANE PROTEINS
ORGANIC COMPOUNDS
PROTEINS
SOMATIC CELLS
STRUCTURAL CHEMICAL ANALYSIS
550400* - Genetics