Gene organization and rearrangements at the human Rhesus blood group locus revealed by fiber-FISH analysis.
The human Rhesus (Rh) blood group locus is composed of two highly homologous genes, the RHD and RHCE genes on chromosome 1, encoding the D, C/c, and E/e antigens in common Rh-positive phenotypes. In general, the RHD gene is either absent or grossly deleted in Rh-negative individuals. In this study, gene organization at the RH locus of Japanese donors with different serological phenotypes was directly analyzed by two-color fluorescence in situ hybridization on DNA fibers released from their lymphocytes (fiber-FISH) and by using DNA probes of introns 3 and 7 of the RHCE and RHD genes. Six Rh-positive samples (two with the D+C-c+E+e-, two with the D+C+c-E-e+, and two with the D+C+c+E+e+ phenotype) showed the presence of two RH genes within a region of less than 200 kb on chromosome 1p36.1. Of great interest was the finding that the genes were arranged in the antidromic order of the telomere -RHCE (5'--> 3') -RHD (3'-->5') - centromere. On the other hand, two typical Rh-negative samples (D-C-c+E+e+) showed the presence of only one RHCE gene, as expected. Moreover, further analysis combined with a locus-specific assay of three Rh-negative samples (D-C+c+E+e+, D-C+c+E-e+, and D-C+c-E-e+) showed the possible presence of the RHD gene(s) and complex rearrangements, including partial deletion, duplication, and recombination, in this region; these could be responsible for the Rh-negative phenotype.
Suto
Y
Y
Department of Research, The Japanese Red Cross Central Blood Center, Tokyo, Japan.
Ishikawa
Y
Y
Hyodo
H
H
Uchikawa
M
M
Juji
T
T
D001483:Base Sequence; D017931:DNA Primers; D015342:DNA Probes; D015321:Gene Rearrangement; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D007438:Introns; D010641:Phenotype; D012204:Rh-Hr Blood-Group System / Q000235:genetics*
D017931:DNA Primers; D015342:DNA Probes; D012204:Rh-Hr Blood-Group System