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>

Application of 17 Y-chromosome specific STR loci in paternity testing / 中国实验血液学杂志

The purpose of this study was to explore the ability of discrimination of the AmpFlSTR Yfiler PCR amplification kit containing 17 Y-STR loci and the allelic mutation in the practice of paternity testing in Chinese population. 36 non-paternity father/son pairs and 84 confirmed father/son pairs, which had been previously genotyped by using Reliagene Y-PLEX 6 commercial kit and the "9 Y-STR multiplex with reduced-size amplicons" developed by our laboratory, were subjected to Y-STR genotyping at 17 loci using the AmpFlSTR Yfiler PCR amplification kit. 17 Y-STR loci were amplified in single multiplex and the PCR products were detected by using ABI Prism 3100 DNA Sequencer. The number of Y-STR exclusion for each non-paternity father/son pair and the mutation events for each confirmed father/son pair were calculated and the observed results were compared with our previous reported data determined by Reliagene Y-PLEX 6 kit and the "9 Y-STR multiplex with reduced-size amplicons". The results showed that out of 36 non-paternity father/son pairs subjected to Y-STR genotyping by using the AmpFlSTR Yfiler kit, one case with no Y-STR exclusion of paternity and 35 cases with more than 3 Y-STR exclusions for each father/son pair were observed. The percentage of cases with more than 3 Y-STR exclusions in all the tested non-paternity cases for Yfiler kit was 97.22% (35/36), which was more than that of Reliagene Y-PLEX 6 kit (92.11%, 35/38) and our "9 Y-STR multiplex with reduced-size amplicons" (91.67%, 33/36). Except for single father/son pair with no Y-STR exclusion, an average of 11.3 Y-STR exclusions was observed in other 35 non-paternity father/son pairs. In the 84 confirmed father/son pairs, 5 mutation events with a single unit repeat change at DYS437, DYS439, DYS635, DYS389II and DYS19, respectively, were identified using the Yfiler kit. The average mutation rate was estimated at 3.50 x 10(-3) per locus per generation. The cases with Y-STR mutation events in all tested confirmed father/son pairs for Yfiler system were 5.95% (5/84), which was significantly higher than that of Y-PLEX 6 (2.15%, 2/93) and "9 Y-STR multiplex with reduced-size amplicons" (no mutation events in the same 84 confirmed father/son pairs). It is concluded that the Yfiler kit which allowing simultaneous analysis of 17 Y-STR loci offers a high ability of discrimination for paternity testing, however, the Y-STR allelic mutation of the Yfiler system can not be neglected.

Genetic status of a AB chimeric blood group family / 中国实验血液学杂志

In order to study the genetic status of a rare chimeric family, some samples of A(3)B(3) family were identified by sequencing of ABO gene; flow-rSSO and PCR-SSP were used to detect loci of HLA-A, B, DRB1 genes, and multiplex amplifying with fluorescence-dye were performed for 16 short tandem repeat (STR) loci. The results indicated that two individuals from A(3)B(3) family contained more than two alleles at ABO gene, HLA-B, DRB1 and some STR loci. In conclusion, analysis of chimeric blood group by using genotyping techniques clearly demonstrating genetic status of this rare chimeric blood group promotes further elucidation of the existing state of specific genetic status.

Effect of platelet CD42a modification by mPEG-SPA with different molecular masses / 南方医科大学学报

<p><b>OBJECTIVE</b>To observe the effect platelet antigen modification by mPEG-SPA with different molecular masses.</p><p><b>METHODS</b>Platelet CD42a was modified by 5 kD and 20 kD mPEG-SPA, respectively, and the fluorescence intensity of CD42a was detect by flow cytometry and the three-dimensional structure of CD42a simulated to analyze the distribution of lysine in CD42a molecule.</p><p><b>RESULTS</b>After platelet CD42a modification by 5 kD and 20 kD mPEG-SPA, the fluorescence intensity of CD42a decreased sharply by 85.54% and 88.65%, respectively, and multiple lysine regions were identified on the surface of CD42a molecule.</p><p><b>CONCLUSION</b>Both 5 kD and 20 kD mPEG-SPA allow useful modification of platelet CD42a, but 20 kD mPEG-SPA is more advantageous than 5 kD mPEG-SPA.</p>

Molecular genetic analysis of Diego blood group Dia and Dib in Chinese Han population / 法医学杂志

OBJECTIVE@#To study the molecular genetic background of Diego blood group in Chinese Han population.@*METHODS@#A total of 2990 blood samples from unrelated blood donors were phenotyped for Dia and Dib by serological method. Twenty randomly selected samples of Di(a-b+) type and all of the samples of rare Di(a+b-) phenotype by screening were genotyped by PCR-SSP and direct DNA Sequencing.@*RESULTS@#Of the 2990 samples identified by serological method, 2821 were Di(a-b+), 167 were Di(a+b+) and 2 were Di(a+b-). All of the 20 randomly-selected samples with Di(a-b+) phenotype were DI2DI2 homozygote by PCR-SSP genotyping, with nucleotide C at nt position 2561 in exon 19 by direct sequencing of the DI gene. The 2 samples of rare Di (a+b-) phenotype were both the DI1DI1 homozygote, with nucleotide T at nt position 2561 in exon 19.@*CONCLUSION@#Our results indicate that the expression of Dia and Dib antigens in Chinese Han population most likely result from a single nucleotide T to C substitution at nucleotide position 2561 in exon 19 of the DI gene, which subsequently leads to an amino acid 854 change from Pro to Leu.