ABSTRACT
BACKGROUND: B(x) is a very rare ABO blood group phenotype and the molecular mechanism underlying it still remains largely unknown. This study reports two novel B(x) alleles in two Chinese individuals. STUDY DESIGN AND METHODS: Serologic investigations including serum transferase activity assay were performed with standard methods. DNA sequences of all seven exons and exon-intron boundaries of ABO gene were analyzed using genomic DNA by polymerase chain reaction and direct DNA sequencing or sequencing after gene cloning. RESULTS: B(x) phenotypes were diagnosed in these two individuals. DNA analysis revealed that the ABO gene of the two B(x) individuals was heterozygous of O01/B alleles. Two novel heterozygous mutations 905A>G and 541T>C were identified, respectively, which resulted in the amino acid changes D302G and W181R in the B glycosyltransferases. The mutations were not found in 120 randomly selected samples. CONCLUSION: Amino acid substitutions resulted from novel mutations 905A>G and 541T>C on ABO gene change highly conserved regions of the enzyme and may reduce the activity of the glycosyltransferases, leading to the B(x) phenotype.
Subject(s)
ABO Blood-Group System/genetics , Alleles , Galactosyltransferases/genetics , Mutation, Missense , Point Mutation , Amino Acid Sequence , Amino Acid Substitution , China , Conserved Sequence , Female , Galactosyltransferases/chemistry , Humans , Molecular Sequence Data , Phenotype , Sequence Alignment , Sequence Analysis, DNA , Sequence Homology, Amino AcidABSTRACT
HLA phenotypes of 26,266 Chinese individuals who were recruited as potential hematopoietic stem cell donors by the Shanghai Red Cross Marrow Donor Registry, part of the China Marrow Donor Program, were determined for HLA-A, -B, and -DRB1 alleles at low to intermediate resolution using DNA-based typing methods. The large sample size of the study allowed accurate calculation of the Chinese HLA haplotype frequencies. The observed alleles correspond to 19 HLA-A, 44 -B, and 13 -DR split antigens. The serologic equivalents of HLA-A36, -A80, -B78, and -DR18 alleles were not observed. A total of 2,241 distinct HLA-A, -B, -DRB1 haplotypes were identified. Three-locus haplotype frequency was estimated using the maximum likelihood method. The lowest haplotype frequency that can be reliably estimated at a 95% confidence level was 0.000057. Using this cutoff value, 1,220 haplotypes (54%) were statistically reliable and their cumulative haplotype frequency was 0.9730. The cumulative haplotype frequency of the remaining 1,021 haplotypes (46%) was 0.0270. A regression equation of p = 0.192 log N - 0.576 was derived to estimate the probability (p) of finding an HLA-A, -B, -DR split antigens-matched donor in a pool of N Chinese donors.
Subject(s)
Bone Marrow/immunology , DNA Fingerprinting , Gene Frequency , HLA-A Antigens/genetics , HLA-B Antigens/genetics , HLA-DR Antigens/genetics , Asian People/genetics , China , Haplotypes , Humans , RegistriesABSTRACT
BACKGROUND & OBJECTIVE: Bcl-2/E1B 19kDa interacting protein3-like (BNIP3L) gene is a tumor suppressor gene cloned from a human fetal liver cDNA library, which is located at 8p21, one of the high frequent regions of loss of heterozygosity (LOH) in lung carcinoma. BNIP3L protein can interact with antiapoptotic proteins, such as Bcl-2, Bcl-x(L), E1B19K, which promotes apoptosis. This study was designed to explore the correlation of alteration of expression and structure of BNIP3L gene with the progression of lung cancer. METHODS: The expression and structure of BNIP3L gene in 4 lung cancer cell strains and 30 tissues were determined by SP immunohistochemistry, immunoblot, semi-quantitative reverse transcription-PCR (RT-PCR), PCR-single strain conformation polymorphism (PCR-SSCP). RESULTS: (1) In 4 lung cancer cell strains, BNIP3L protein was not detected in A549, NCI-H460, NCI-H446, except for NCI-H520, in which the protein expression level was slightly lower than that in immortal bronchial epithelial cell strain HBE4-E6/E7. BNIP3L protein was observed in 46.7% (14/30) lung cancer tissues, while 100% (12/12) in normal lung tissues. The difference was significant in statistics (P< 0.05). (2) BNIP3L mRNA was detected in 4 lung cancer cell strains; and there existed no obvious discrepancy of the amount between these cell strains and HBE4-E6/E7. Absence or decrease of BNIP3L mRNA was observed in 26.7%(8/30) of lung cancer tissues. The average quantity of BNIP3L mRNA was 0.404+/-0.070 in lung cancer tissues, while 0.575+/-0.065 in paired normal lung tissues. The difference was significant in statistics (P< 0.05). In all the cancerous cell strains and tissues with BNIP3L mRNA, the products of RT-PCR were as long as those from their control samples in size, including the entire coding region, and no variation of BNIP3L gene structure such as absence, rearrangement, aberrant splicing were detected.(3) No point mutation was detected in all 6 exons of BNIP3L gene in 4 lung cancer cell strains and 30 tissues. CONCLUSION: BNIP3L protein expression was down-regulated in lung cancer, which might be involved in the occurrence and/or development of lung cancer. The down-regulation of BNIP3L protein expression in lung cancer was partly caused by the down-regulation of its transcription. The variation of gene structure may be not the reason of BNIP3L inactivity in lung cancer.
