[Generation of RHD-CE(2-9)-D allele by gene conversion in cis].
Previously a few Rh-negative individuals in Caucasian and Chinese were found existing exons 1 and 10 of RHD through genomic DNA testing. The molecular mechanisms, however, remain disputed. In this study, 2 individuals carrying RHD positive, D antigen negative allele (with exon 1 and 10 of RHD) and their mRNA were investigated by using reverse transcriptase PCR (RT-PCR) and sequencing through one pair of specific primers for 5'- and 3'-non-coding region of RHD, taking a Rh-positive (Ccee) sample as control. As a result, the control sample had a normal RHD mRNA, whereas other transcripts were detected in both RHD-positive, D antigen negative individuals, which have same length and exons as the normal RHD or RHCE mRNA. Those transcripts had the same sequences with RHD in exon 1 and exon 10, while the sequences in exons 2-9 were in concordance with RHCE(e) mRNA. It indicated that a hybrid RHD allele, RHD-CE(2-9)-D, was existed in the 2 individuals, in which the exons 2-9 of RHD were substituted by homologous RHCE(e). Thus, this allele could not code normal RhD protein and therefore resulted in Rh-negative phenotype.
Shao
Chao-Peng
CP
Shenzhen Blood Center and Shenzhen Institute of Transfusion Medicine, Shenzhen 518035, China. cpshaos@hotmail.com
Li
Zhen
Z
Xiong
Wen
W
Zhou
Yi-Yan
YY
Li
Xue-Mei
XM
D000483:Alleles; D001483:Base Sequence; D018076:DNA, Complementary / Q000235:genetics*; D005091:Exons; D005785:Gene Conversion; D006801:Humans; D008957:Models, Genetic; D008969:Molecular Sequence Data; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012204:Rh-Hr Blood-Group System / Q000032:analysis / Q000235:genetics* / Q000378:metabolism; D017422:Sequence Analysis, DNA
D018076:DNA, Complementary; D012333:RNA, Messenger; D012204:Rh-Hr Blood-Group System; C026410:Rho(D) antigen