Class I gene contraction within the HLA-A subregion of the human MHC.
Individuals expressing either the HLA-A24 or the HLA-A23 histocompatibility antigens have been found to possess an HLA-A class I subregion approximately 50 kb smaller in size than those studied from individuals expressing other HLA-A haplotypes. This originally manifested itself as a haplotype-associated size variation in the NotI and MluI megabase fragments observed on pulsed-field electrophoresis gels after blotting and probing with HLA-A subregion-specific genomic probes. The contracted region falls between the HLA-A and the HLA-G class I genes and specifically includes the novel HLA-A-related pseudogene, HLA-H, as well as the adjacent deteriorated class I pseudogene, 7.0 p. The intactness of locus D6S128, defined by probe pMC6.7 located telomeric to the HLA-H gene, demonstrates that the distal rearrangement point falls within a 20-kb stretch of DNA separating HLA-H from pMC6.7. This extends a previous report regarding variation in class I gene number within the human major histocompatibility complex and precisely localizes the genomic residence of sequences that may define a recombination hot spot. Because the size variation maps to a recombinogenic area, its characterization may ultimately reveal important biological information relevant to the events that shaped the organization of the human HLA class I multigene family.
Department of Microbiology and Immunology, Pennsylvania State University College of Medicine, Milton S. Hershey Medical Center, Hershey 17033.
C P
CP
Venditti
M J
MJ
Chorney
D015139:Blotting, Southern; D003429:Cross Reactions; D005805:Genes, MHC Class I; D015234:HLA-A Antigens / Q000235:genetics*; D006239:Haplotypes; D006801:Humans; D008285:Major Histocompatibility Complex / Q000235:genetics*; D012150:Polymorphism, Restriction Fragment Length; D011544:Pseudogenes
D015234:HLA-A Antigens