Molecular analysis and polymorphism of the DLA‐DQB genes

Abstract

Partial-length cDNA clones and full-length genomic clones corresponding to a complete canine DQB class II gene were isolated. Southern analyses suggested the presence of two DQB genes--one of which appeared to be a pseudogene lacking exon 2 called DQB2. The other DQB gene, called DQB1, was isolated from a genomic phage clone and contained six exons. The DQB1 clone was restriction mapped, and exon 2 was sequenced from 70 dogs. Twenty alleles were found. Most of the amino acid substitutions occurred at putative positions in the peptide binding site. Inheritance of these sequences showed Mendelian segregation with one or two alleles per dog. Cluster analysis of the nucleotide and predicted amino acid sequences subdivided the canine DQB1 alleles into four major allelic groups. The number of nonsynonymous changes was higher than the number of synonymous changes in the putative antigen recognition sites suggestive of positive selection.

Molecular characterization of expressed DQA and DQB genes in the California sea lion ( Zalophus californianus )

“…In addition, the distribution of the polymorphic residues in sea lions was different from that reported in other species. This confirms findings in other pinniped species (Slade 1992), but contrasts sharply with the corresponding himian and canine DQ genes (Robinson 2001;Polvi et al 1997;Wagner et al, 1998Wagner et al, , 1999. The disparity between the extent and distribution of sequence heterogeneity between the sea lion and the domestic dog, the closest relative with an extensively characterized MHC (Schreiber et al 1998;Wagner et al 1999), is particu-larly significant because it contradicts the well-established concept of shared residues and motifs within and between species Erlich and Gyllensten 1991;Fan et al 1989;Gustafsson et al 1990;Kupfermann et al 1992;Slierendregt et al 1992;Yaeger and Hughes 1999).…”

“…These genes were selected because trans-species conservation of class II MHC sequences has been shown in other mammals Erlich and Gyllensten 1991;Fan 1989;Gustafsson et al 1990; Kupfermann et al 1992;Slierendregt et al 1992;Yaeger and Hughes 1999). While there is limited information regarding the MHC of species closely related to the California sea lion (order/suborder Camivora/Caniformia/ Pinnipedia) (McKenna and Bell 1997), the class II MHC genes of a related terrestrial carnivore, the domestic dog (order/suborder Camivora/Caniformia/Canidae); Schreiber et al 1998), have been extensively studied (Polvi et al 1997;Sarmiento et al 1992Sarmiento et al , 1993Wagner et al 1996Wagner et al , 1998Wagner et al , 1999. These studies show that the canine DQA and DQB gene products are polymorphic, and may be important in generating peptide-binding diversity.…”

Tolerance to Vascularized Composite Allografts in Canine Mixed Hematopoietic Chimeras

“…Five littermate donor/recipient pairs were DLA-identical on the basis of matching for highly polymorphic major histocompatibility complex (MHC) class I and class II micro-satellite markers (44). In addition, specific DLA DRB1 allelic identity was confirmed by direct sequencing (45). …”

A review of immunologic diseases of the dog

“…DLA-88 has at least 40 alleles, while the other class I loci have fewer than 12 alleles. Within the dog MHC class II, region, clear homologues have been identified for human DRA, DRB, DQA, and DQB (Kennedy et al, 1998a, b;Polvi et al, 1997;Sarmiento et al, 1990Sarmiento et al, , 1992Sarmiento et al, , 1993Wagner et al, 1996aWagner et al, , b, 1998. There are two genes in the DQ region, DQA1 and DQB1, and one gene in the DR region, DRB1.…”