Establishment of an assay for cloning and sequencing the full-length HLA-Cw gene / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To establish a reliable assay for cloning and sequencing the full-length HLA-Cw gene.</p><p><b>METHODS</b>In this study, a fragment of 4.5 kb full-length HLA-Cw gene was amplified using the self-designed PCR primer pair by long template PCR, purified PCR products was cloned into the pGEM-Teasy plasmid vector and the plasmid DNA isolated from positive clones was subjected to haplotype sequencing by both directions. A total of 12 samples having been previously-genotyped by PCR sequence-based-typing (PCR-SBT) were amplified by using the TaKaRa LA Taq and Stratagene Pfu polymerase, respectively. PCR products of full length HLA-Cw gene were subjected to cloning and sequencing and the obtained haplotype sequence were compared with the PCR-SBT results.</p><p><b>RESULTS</b>The specific target fragment of HLA-Cw gene could be amplified and the full-length HLA-Cw allele sequence covering from nucleotide position -962 in 5'untranslated region (5'-UTR) to nucleotide position 3576 in downstream area of 3'-UTR region could be obtained using our method. The results of cloning and sequencing analysis indicated that the Stratagene Pfu polymerase had better fidelity than the TaKaRa LA Taq polymerase in this experiment. By comparing the sequences of Cw*07020101 with Cw*010201, 11 SNPs as well as 2 insertions/deletions in nt-962--284 of 5'-UTR, and 11 SNPs as well as 1 insertion/deletion in nt3067-3576 downstream of 3'-UTR were identified.</p><p><b>CONCLUSION</b>Our results indicate that the technique for cloning and sequencing full-length HLA-Cw gene has been established, it has a broad application in full-length HLA-Cw gene polymorphism study and the regulation and expression of HLA-Cw gene.</p>

An analysis of the reason for HLA-C allele dropout in five samples by sequence-based typing / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To analyze the possible reason for HLA-C allele dropout in routine sequence-based typing (SBT) and improve the accuracy of HLA-C SBT test.</p><p><b>METHODS</b>A total of 620 randomly selected samples from healthy voluntary blood donors in Shenzhen were typed at HLA-C locus by sequence-based typing using the AlleleSEQR HLA-C plus sequence-based typing kit. Samples with no full match result were subjected to cloning and haplotype sequencing of the full-length HLA-C gene. If no novel mutations were found, samples were then retyped, using our self-designed PCR primer pair and PCR conditions replacing the AlleleSEQR HLA-C PCR reagents in the PCR set-up procedure so as to analyze the potential reasons for causing abnormal SBT result.</p><p><b>RESULTS</b>In the 620 samples typed at HLA-C locus using the AlleleSEQR HLA-C SBT commercial kit, 5 samples with no full match result were identified. The closest genotype showed one nucleotide mismatch with many different allele groups at different nucleotide position. Based on the PCR-SBT nucleotide sequence, heterozygous nucleotides were determined only in exon 4, whereas the nucleotides in exon 2 and 3 were all homozygotes. The results showed that HLA-Cw*0706 allele dropout existed in all the 5 samples with abnormal SBT results initially identified by AlleleSEQR HLA-C SBT kit, no novel mutation was found.</p><p><b>CONCLUSION</b>The results indicate that the PCR primer pair incompatible with DNA template may result in allele dropout in HLA-C SBT test. Based on the characterization of HLA-C full-length, it is essential to develop HLA-C SBT kit suitable for Chinese population in the future.</p>

Analysis on expression and molecular basis for ABO glycosyltransferase with dual specificity / 中国实验血液学杂志

In order to elucidate the expression and molecular genetic background of ABO gene seven samples with ABO discrepancy further identified as bi-specific ABO gene were studied. All these samples were subjected to phenotyping by monoclonal and polyclonal antisera and were then genotyped by direct DNA sequencing and haplotype-sequencing at the exon 6 and 7 of ABO gene. As a result, six ABO dual-specific alleles were identified in Chinese population. An antigen expressed by these B (A) or Cis-AB individuals varied from very low level to the normal level, compared with common A blood group samples. In conclusion, molecular genetic backgrounds of two pairs out of four samples in all samples were the same, however, the ABO expression showed diverse.

Genetic polymorphism of 9 Y-STR loci with short fragment size alleles in unrelated male individuals from Zhuang ethnic group / 中国实验血液学杂志

The aim of this study was to investigate the genetic polymorphism of Y-chromosome specific short tandem repeat (Y-STR) loci in Zhuang ethnic group of China. Nine Y-STR loci were amplified by single multiplex and the PCR products were detected by using ABI Prism(TM) 3100 DNA Sequencer. The allele frequencies and haplotype frequencies at 9 Y-STR loci were determined in a total of 85 unrelated male individuals from Zhuang ethnic group of China. The results indicated that in the 85 unrelated male individuals, except for the DYS426 locus with a low GD value, the GD values for other 8 Y-STR loci ranged from 0.4387 to 0.8129. A total of 70 haplotypes at 9 Y-STR loci were found, the haplotype diversity was 0.9926. It is concluded that the haplotype polymorphism of 9 Y-STR loci are highly polymorphic in Zhuang ethnic group and also significantly different from our previous reported data of unrelated male individnals in southern Chinese Han population.

Genotyping of ABO loci in para-Bombay type individuals / 中国实验血液学杂志

To study the molecular genetic basis of ABO alleles in para-Bombay type individuals, samples from five para-Bombay type individuals identified by serologic tests including absorption-elution tests, saliva neutralizing or inhibitor substances tests, were genotyped by using PCR-SSP based ABO genotyping. Exon 6 and exon 7 at the ABO locus for all 5 samples were sequenced. The results showed that the ABO genotypes of five para-Bombay samples were A102B1, A102B1, A102O1, A102B1, B1O1 respectively, the direct DNA sequencing results were in accordance with the results genotyped by PCR-SSP method, No novel nucleotide mutation was found at the exon 6 and exon 7 of ABO gene. In conclusion, the ABO genotyping assay by PCR-SSP provide a simple, rapid and accurate method for determining the ABO type of para-Bombay cases.