scholarly journals Genomic V-gene repertoire in reptiles

2014 ◽  
Author(s):  
David N Olivieri ◽  
Bernardo von Haeften ◽  
Christian Sánchez-Espinel ◽  
Jose Faro ◽  
Francisco Gambón-Deza
Keyword(s):  
T Cell Receptor ◽  
Cell Receptor ◽  
Gene Repertoire ◽  
Gamma Delta ◽  
Terrestrial Vertebrates ◽  
Evolutionary Diversification ◽  
Representative Species ◽  
V Genes ◽  
V Gene ◽  
Evolutionary Lineages

Reptiles and mammals diverged over 300 million years ago, creating two parallel evolutionary lineages amongst terrestrial vertebrates. In reptiles, two main evolutionary lines emerged, one gave rise to Squamata, while the other gave rise to Testudines, Crocodylia and birds. In this study, we determined the genomic variable (V)-gene repertoire in reptiles corresponding to the three main immunoglobulin (Ig) loci and the four main T-cell receptor (TCR) loci. We show that squamata lack the TCR gamma/\delta genes and snakes lack the V-kappa genes. In representative species of testudines and crocodiles, the seven major Ig and TCR loci are maintained. As in mammals, genes of the Ig loci can be grouped into well-defined clans through a multi-species phylogenetic analysis. We show that the reptile VH and V-lambda genes are distributed amongst the established mammalian clans, while their V-kappa genes are found within a single clan, nearly exclusive from the mammalian sequences. The reptile and mammal V-genes of the TRA locus cluster into six common evolutionary clans. In contrast, the reptile V-genes from the TRB locus cluster into three clans, which have few mammalian members. In this locus, the V-gene sequences from mammals appear to have undergone different evolutionary diversification processes that occurred outside these shared reptile clans.

scholarly journals Allelic variations in the human T cell receptor V beta 6.7 gene products.

1990 ◽  
Vol 171 (1) ◽  
pp. 221-230 ◽  
Author(s):  
Y Li ◽  
P Szabo ◽  
M A Robinson ◽  
B Dong ◽  
D N Posnett
Keyword(s):  
Immune Responses ◽  
T Cell Receptor ◽  
Cell Receptor ◽  
Gene Products ◽  
Human T Cell ◽  
Direct Demonstration ◽  
Disease Associations ◽  
V Genes ◽  
V Gene ◽  
Allelic Variations

Polymorphisms of human TCR gene products have been suggested by the description of a mAb, OT145, that identifies a subset of TCRs in some individuals but not in others (6). Here we demonstrate that this mAb detects a TCR allotype of the V beta 6.7 gene. Two allelic products of this V gene differ by two nonconservative amino acid substitutions. The mAb OT145 appears to react with V beta 6.7 a gene products ("+" allele), but not with V beta 6.7b gene products ("-" allele). This represents the first direct demonstration that TCR V gene allotypes exist and provides a possible explanation for immune responses under the control of TCR V genes and for disease associations with TCR V genes.

scholarly journals The immunologic V-gene repertoire in mammals

2014 ◽  
Author(s):  
David N Olivieri ◽  
Bernardo von Haeften ◽  
Christian Sánchez-Espinel ◽  
Francisco Gambón-Deza
Keyword(s):  
Mammalian Species ◽  
Cell Receptor ◽  
Gene Repertoire ◽  
The Public ◽  
Phylogenetic Studies ◽  
Kappa Chain ◽  
Show Evidence ◽  
V Genes ◽  
V Gene ◽  
Additional Locus

From recent whole genome shotgun data of 48 mammalian species, we have used our software VgenExtractor to obtain the functional V-gene sequence repertoire in order to conduct comparative phylogenetic studies. These studies reveal a large variation in the number of V-genes across mammalian species, ranging from a mere 36 V-genes in dolphins to nearly 600 V-genes in rats. Monotremes and marsupials are the only mammals possessing an additional locus, the TRMV, apart from the seven common loci found in mammals. Also, we show evidence for the loss of the light chain loci, specifically the V-kappa chain in one microbat, and the V-lambda chain in one rodent species. Finally, we suggest different features related to the evolution of immunoglobulin and T cell receptor loci, where frequent sequence duplications are seen in the former, while preserved and undiversified lineages are observed in the latter. All the V-gene sequences described in this study are available in the public database repository vgenerepertoire.org.

scholarly journals Diversity and organization of human T cell receptor delta variable gene segments.

1989 ◽  
Vol 169 (1) ◽  
pp. 41-57 ◽  
Author(s):  
S Hata ◽  
M Clabby ◽  
P Devlin ◽  
H Spits ◽  
J E De Vries ◽  
...  
Keyword(s):  
T Cell Receptor ◽  
Blot Hybridization ◽  
Gene Segment ◽  
Cell Receptor ◽  
Gene Repertoire ◽  
Gamma Delta ◽  
Inverted Orientation ◽  
Human T Cell ◽  
Delta Gene ◽  
Variable Gene

Previous studies of the human TCR-delta gene identified a single commonly used V delta segment, denoted V delta 1. To better understand the extent of the human TCR-delta V gene repertoire, TCR-delta transcripts and gene rearrangements were examined in a new panel of cloned human TCR-gamma/delta lymphocytes. Through this analysis we identified and determined the structures of two new V delta segments, denoted V delta 2 and V delta 3. These V delta segments are different from previously characterized V alpha segments, supporting the notion that the human V delta and V alpha repertoires are distinct. Examination of V gamma gene segment usage in these cells reveals that the V delta 2 gene segment is used in conjunction with the V gamma 2 gene segment. Blot hybridization indicates that the V delta 2 gene segment lies between V delta 1 and D delta-J delta-C delta, and within 100 kb of the latter. Analysis of genomic clones indicates that the V delta 3 gene segment lies in an inverted orientation, approximately 2 kb 3' of C delta. This implies that rearrangement of V delta 3 to D delta-J delta-C delta occurs by inversion. Together with previous mapping studies, these results indicate that human V delta segments are dispersed, rather than clustered, within the TCR-alpha/delta locus. The analysis of rearrangements in polyclonal thymocyte DNA suggests that there may be a limited number of additional V delta gene segments yet to be characterized.

scholarly journals Characterization of excised DNA intermediates associated with V(D)J recombination at the T-cell receptor delta locus.

1997 ◽  
Vol 17 (5) ◽  
pp. 2631-2641 ◽  
Author(s):  
P B Nakajima ◽  
M J Bosma
Keyword(s):  
T Cells ◽  
T Cell ◽  
T Cell Receptor ◽  
Cell Receptor ◽  
Strand Break ◽  
Gene Repertoire ◽  
Gammadelta T Cells ◽  
Recombination Signal Sequences ◽  
V Gene

Lymphocyte development requires the assembly of antigen receptor genes through the specialized process of V(D)J recombination. This process is initiated by cleavage at the junction between coding segments (V, D, and J) and the recombination signal sequences that border these segments, resulting in generation of double-strand break intermediates. We have used a two-dimensional gel system to characterize broken molecules arising from V(D)J recombination at the T-cell receptor (TCR) delta locus and have identified linear species excised by Ddelta1-Ddelta2 and V-Ddelta2 rearrangement in thymus DNA. Relatively few (approximately 10) V-Ddelta2-excised linear species were detected in DNA from fetal thymocytes. The sizes of these species corresponded to the estimated distances between Ddelta2 and the V gene segments utilized by gammadelta T cells and indicated that both Ddelta2-proximal and -distal V gene segments are targeted for V-Ddelta2 rearrangement. Similar-sized species were observed in DNA from thymocytes of scid mice in which T-cell development is arrested prior to TCR expression. Since previous studies suggest that the TCR alpha/delta locus encodes more than 100 V gene segments, our results indicate that a few select V gene segments are predominantly targeted for rearrangement to Ddelta2, and this primarily accounts for the restricted Vdelta gene repertoire of gammadelta T cells.

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