Major histocompatibility complex and immunoglobulin loci visualized by in situ hybridization on Xenopus chromosomes

Courtet, Michéle; Flajnik, Martin F.; Pasquier, Louis Du

doi:10.1016/s0145-305x(00)00045-8

Cited by 55 publications

(63 citation statements)

References 25 publications

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“…The same feature is found for the Xenopus MHC, in which only one class I gene of the classical type is MHC linked (49), while a large set of linked nonclassical class I genes is found in another gene complex half a chromosome away (50,51). In chickens, two class I genes (one highly expressed) sandwich the TAP1 and TAP2 genes, and Kaufman and colleagues (11,21,52) have proposed that the tight linkage has allowed the particular class I and TAP alleles to coevolve; furthermore, like in frogs, several nonclassical chicken class I genes are found a great distance away from the true MHC on the same chromosome (53).…”

Section: Figure 11supporting

confidence: 57%

Proteasome, Transporter Associated with Antigen Processing, and Class I Genes in the Nurse SharkGinglymostoma cirratum: Evidence for a Stable Class I Region and MHC Haplotype Lineages

Ohta

McKinney

Criscitiello

et al. 2002

The Journal of Immunology

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Cartilaginous fish (e.g., sharks) are derived from the oldest vertebrate ancestor having an adaptive immune system, and thus are key models for examining MHC evolution. Previously, family studies in two shark species showed that classical class I (UAA) and class II genes are genetically linked. In this study, we show that proteasome genes LMP2 and LMP7, shark-specific LMP7-like, and the TAP1/2 genes are linked to class I/II. Functional LMP7 and LMP7-like genes, as well as multiple LMP2 genes or gene fragments, are found only in some sharks, suggesting that different sets of peptides might be generated depending upon inherited MHC haplotypes. Cosmid clones bearing the MHC-linked classical class I genes were isolated and shown to contain proteasome gene fragments. A non-MHC-linked LMP7 gene also was identified on another cosmid, but only two exons of this gene were detected, closely linked to a class I pseudogene (UAA-NC2); this region probably resulted from a recent duplication and translocation from the functional MHC. Tight linkage of proteasome and class I genes, in comparison with gene organizations of other vertebrates, suggests a primordial MHC organization. Another nonclassical class I gene (UAA-NC1) was detected that is linked neither to MHC nor to UAA-NC2; its high level of sequence similarity to UAA suggests that UAA-NC1 also was recently derived from UAA and translocated from MHC. These data further support the principle of a primordial class I region with few class I genes. Finally, multiple paternities in one family were demonstrated, with potential segregation distortions.

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Section: Figure 11supporting

confidence: 57%

Proteasome, Transporter Associated with Antigen Processing, and Class I Genes in the Nurse SharkGinglymostoma cirratum: Evidence for a Stable Class I Region and MHC Haplotype Lineages

Ohta

McKinney

Criscitiello

et al. 2002

The Journal of Immunology

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“…Genetic separation of the two class I subclasses could be a means by which the integrity of class Ia and class Ib loci are maintained. Perhaps the class Ia loci isolated by this arrangement evolve in concert with adjacent Ag processing loci as has been suggested by others (47,48), whereas the class Ib loci are free to evolve in a different manner. In isolation the class Ib loci may be able to change in number, allelic variation, and ABR specificity through a variety of recombination events in a system for selective Ag presentation that evolves rapidly in response to disease challenge.…”

Section: Discussionmentioning

confidence: 60%

At Least One Class I Gene in Restriction Fragment Pattern-Y (Rfp-Y), the SecondMHCGene Cluster in the Chicken, Is Transcribed, Polymorphic, and Shows Divergent Specialization in Antigen Binding Region

Afanassieff

Goto

et al. 2001

The Journal of Immunology

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MHC genes in the chicken are arranged into two genetically independent clusters located on the same chromosome. These are the classical B system and restriction fragment pattern-Y (Rfp-Y), a second cluster of MHC genes identified recently through DNA hybridization. Because small numbers of MHC class I and class II genes are present in both B and Rfp-Y, the two clusters might be the result of duplication of an entire chromosomal segment. We subcloned, sequenced, and analyzed the expression of two class I loci mapping to Rfp-Y to determine whether Rfp-Y should be considered either as a second, classical MHC or as a region containing specialized MHC-like genes, such as class Ib genes. The Rfp-Y genes are highly similar to each other (93%) and to classical class Ia genes (73% with chicken B class I; 49% with HLA-A). One locus is disrupted and unexpressed. The other, YFV, is widely transcribed and polymorphic. Mature YFV protein associated with β2m arrives on the surface of chicken B (RP9) lymphoma cells expressing YFV as an epitope-tagged transgene. Substitutions in the YFV Ag-binding region (ABR) occur at four of the eight highly conserved residues that are essential for binding of peptide-Ag in the class Ia molecules. Therefore, it is unlikely that Ag is bound in the YFV ABR in the manner typical of class Ia molecules. This ABR specialization indicates that even though YFV is polymorphic and widely transcribed, it is, in fact, a class Ib gene, and Rfp-Y is a region containing MHC genes of specialized function.

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“…The Xenopus A6 kidney cell line was obtained from ATCC (CCL 102). The 15/0 lymphoid tumor line is derived from a spontaneously arising thymic tumor in an LG-15 frog [26,35]. gp96 was derived from either LG-15 Xenopus liver or from 15/0 solid tumors grown in LG-15 frogs.…”

Section: Animals Tumor Cell Lines and Gp96mentioning

confidence: 99%

“…In Xenopus there are roughly 20 class Ib genes [25]; these are distant from the MHC locus but located at the telomeric extremity of the same chromosome [26]. Xenopus nonclassical MHC class Ib (XNC) genes, like their mammalian counterparts, are heterogeneous, have a low polymorphism (especially in the peptide-binding domain) and have more restricted tissue distribution than class Ia molecules.…”

Section: Introductionmentioning

confidence: 99%

Involvement of nonclassical MHC class Ib molecules in heat shock protein‐mediated anti‐tumor responses

et al. 2007

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Nonclassical MHC class Ib (class Ib) genes are found in all jawed vertebrates, and their products are hypothesized to be indicators of intracellular stress and malignancy. They may be involved in immune recognition of classical MHC class Ia (class Ia)‐low or ‐negative tumor cells through their interaction with T cell receptors and/or non‐T cell inhibitory or triggering receptors expressed by NK cells and T cells. In the frog Xenopus, the molecular chaperone gp96 mediates a potent immune response involving antigen‐specific classical class Ia‐unrestricted CD8+ CTL (CCU‐CTL) against a transplantable thymic tumor (15/0) that does not express class Ia molecules. We hypothesized that Xenopus nonclassical class Ib gene products (XNC) are involved in gp96‐mediated CCU‐CTL anti‐tumor responses. To investigate the involvement of class Ib gene products in Xenopus anti‐tumor responses, we generated, for the first time in ectothermic vertebrates, stable tumor transfectants expressing short hairpin RNA (shRNA) to silence either XNC directly or β2m to prevent class Ib surface expression. Both types of 15/0 transfectants are more resistant to CCU‐CTL killing, more tumorigenic and more susceptible to NK‐like cell killing. This study provides in vitro and in vivo evidence of the evolutionary conservation of class Ib involvement in anti‐tumor CD8+ T cell responses.

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Major histocompatibility complex and immunoglobulin loci visualized by in situ hybridization on Xenopus chromosomes

Cited by 55 publications

References 25 publications

Proteasome, Transporter Associated with Antigen Processing, and Class I Genes in the Nurse SharkGinglymostoma cirratum: Evidence for a Stable Class I Region and MHC Haplotype Lineages

Proteasome, Transporter Associated with Antigen Processing, and Class I Genes in the Nurse SharkGinglymostoma cirratum: Evidence for a Stable Class I Region and MHC Haplotype Lineages

At Least One Class I Gene in Restriction Fragment Pattern-Y (Rfp-Y), the SecondMHCGene Cluster in the Chicken, Is Transcribed, Polymorphic, and Shows Divergent Specialization in Antigen Binding Region

Involvement of nonclassical MHC class Ib molecules in heat shock protein‐mediated anti‐tumor responses

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