Class II genes of miniature swine

Abstract

Class II genes of miniature swine have been characterized by restriction fragment length polymorphism (RFLP) analysis and by analysis of a series of clones isolated from a lymphocyte genomic library. For RFLP analysis, DNA samples from three independent major histocompatibility complex homozygous lines and three intra-MHC recombinant lines were digested with a variety of restriction enzymes and analyzed in Southern blots using human cDNA probes for DP, DQ, DR, and DZ alpha genes, and DP, DQ, DR, and DO beta genes. One, or at most two, unique fragments were detected by hybridization with each of the human alpha probes tested. In contrast, multiple bands (five to six for most enzymes examined) were detected by each of the human beta probes tested, the majority of which were found to cross-react with at least three of these probes under conditions of moderate stringency. Genomic DNA from the SLAc haplotype was cloned into an EMBL-3 bacteriophage vector, and the corresponding genomic library was screened with each of these human cDNA probes. The class II genes thereby isolated from this library showed characteristics consistent with those anticipated from the RFLP analysis. Thus, unique alpha genes were obtained which showed no evidence of cross-hybridization, while beta genes showed extensive cross-hybridization and were frequently detected in the library by more than one human beta gene probe. These data are consistent with early evolutionary divergence of alpha genes, prior to mammalian speciation, and with continuing evolution of beta genes, with possible shared usage of these genes by different alpha loci. The data also imply that alpha genes can readily be assigned to loci homologous to their human counterparts, but that beta genes will require further mapping and/or sequence analysis to confirm assignments.

Structure of miniature swine class II DRB genes: conservation of hypervariable amino acid residues between distantly related mammalian species.

“…Because these results suggest the possibility of modifying transplantation immunity by genetic engineering of SLA class II genes, we have recently begun a detailed analysis of porcine class II genes in miniature swine. Clones encoding class II genes both from an SLAC genomic library (8,9) and from SLA' and SLAd cDNA libraries (10)(11)(12) have been isolated and characterized. We report here the primary structure of two allelic miniature swine DRB genes and note a surprising similarity of both alleles to a single human DRBI allele (DRBIJ-101).…”

RFLP analysis of SLA haplotypes in Swiss large white and American Hampshire pigs using SLA class I and class II probes

“…One to two monomorphic restriction fragments have been observed in Southern blot hybridizations of miniature and domestic pigs using the human DRA probe Downloaded by [University of Florida] at 07:37 01 June 2016 (Sachs et al 1988;Chardon et al 1985). In this study, two to five polymorphic fragments were observed with the porcine DRA probe.…”

“…To our knowledge, only 1 or 2 restriction fragments have been identified in a given individual using the human DQA probe in both miniature swine and domestic swine (Sachs et al 1988;Chardon et al 1985). In our study, the porcine DQA cDNA probe yielded 7 different restriction fragments using Taql restriction enzyme.…”

“…The genes identified for class II antigens include DQA, DQB, DRA and DRB (Osborne et a7. 1983;Sachs et al 1988;Pratt et al 1990;Hirsch et al 1990;Gustafsson et al 1990). …”

The alpha chain gene of H-2O has an unexpected location in the major histocompatibility complex.

“…The present observation that the two H-20 genes, like their human counterparts HLA-DNA and HLA-DOB, are separated by a duster of genes that are involved in antigen processing and peptide transport for class I molecules, raises the possibility that the H-20 genes are more ancient than the class I-related duster of genes, which must have been introduced into the MHC region before speciation. Nonetheless, the occurrence of H-20 genes in all species examined (17,(19)(20)(21)(22) strongly argues for these genes having remained functional during evolution. I CCACTCACCCCAGCA ATG GTC CTT TTT GTG GAG CTG GTC CCG GTA CTC CTA ACC GTA ATG AGC Met Val Leu Phe Val Glu Leu Val Pro Val Leu Leu Thr Val Met Set -10 64 TTC CTG AGT CCC CGA GGA GTA AGG GCC ATC AAG ~CC GAC CAC ATG GGC TCC TAT GGA CCG Phe Leu Set Pro Arg Gly Val Arg Ala Ile Lys Ala Asp His Met Gly SeE Tyr Gly Pro II -1 +1 124 C~C TTC TAC CAA TCT TAC GAC GCT TCT GGA CAG TTC ACA CAC GAA TTT GAC GGG GAA Thr--*Ile (23).…”