A new mechanism for generating TCR diversity: A TCR Jalpha-like gene that inserts partial nucleotide sequences in a D-gene manner.
delta-TCR genes of two gammadelta-T cell hybridomas were found to contain an identical 19-nt sequence in their non-germline N-regions. To determine if this sequence represented a third murine TCR Ddelta gene, genomic PCR was performed by using it as a primer together with primers for interspersed repetitive elements (IRE). Sequencing revealed that the 19-nt segment is part of a 61-nt gene with flanking 5' and 3' recombination signaling sequences (RSS). Southern blot analysis confirmed the presence of this 61-nt gene in the genome of several mouse strains. The gene is unusual in that the distal 24 nucleotides of its 3' RSS region are contributed by the 5' portion of a B2 IRE sequence that includes an apparently non-functional RNA splice site within the 3' nonamer sequence. It has sequence similarities with the Ddelta1 gene (81%) at its 5' end and with Jalpha genes (73%) overall. Tyramide-FISH analysis identified the gene to exist within or adjacent to the TCR alpha/delta locus on chromosome 14. Surveys of available TCR sequences reveal possible partial insertions of the 61-nt gene in other delta-TCR and in alpha-TCR gene sequences. Thus, the unique 61-nt gene is Jalpha gene-like in structure but D gene-like in function.
Reardon
Christopher L
CL
Department of Dermatology, Carl T. Hayden VA Medical Center, 650 Indian School Road, Phoenix, AZ 85012-1892, USA. christopher.reardon@med.va.gov
Hu
Ling-Jia
LJ
Yin
Xiang
X
Born
Willi K
WK
Arden
Bernhard
B
O'Brien
Rebecca
R
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D015332:Gene Rearrangement, alpha-Chain T-Cell Antigen Receptor; D019673:Genes, T-Cell Receptor alpha; D019676:Genes, T-Cell Receptor delta; D007144:Immunoglobulin J-Chains / Q000235:genetics*; D051379:Mice; D008810:Mice, Inbred C57BL; D008969:Molecular Sequence Data; D011948:Receptors, Antigen, T-Cell / Q000235:genetics*
D007144:Immunoglobulin J-Chains; D011948:Receptors, Antigen, T-Cell