Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:2.7.7.7 (DNA polymerase)
 17,007 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

DR6 is a complex allele family composed of at least 16 different alleles. Although 25% of Koreans express DR6 alleles, this allele family has not been well studied in the population. DNA samples obtained from 252 unrelated individuals were screened by PCR using Taq DNA polymerase and a DRB1 group-specific PCR primer set that amplifies the polymorphic second exon of DR3, DR11, and DR6 DRB1 alleles. To identify the DR6 allelic frequencies in this population, PCR-positive samples were further analyzed by dot-blot hybridization using digoxigenin-labeled SSOPs. In this process, a new DRB1 allele was identified by its unique hybridization pattern and was further characterized by direct sequencing after PCR. The new DRB1 sequence is similar to DRB1*1101, differing at codon 47 (TAC[Tyr]/TTC[Phe]) and at codon 58 (GCC[Ala]/GAG[Glu]). Based on sequence comparisons as well as its DRB3 and DQ associations, the new allele may have arisen by a gene conversion event from DRB1*1101. The resultant DR molecule bears DR6 serologic determinants as determined by serologic typing and, based on sequence, is probably a DR13 and not a DR14 allele. These data suggest that the DR11 allele has frequently acted as a recipient gene in the gene conversion events that created the subfamily of DR13 alleles, DRB1*1303, *1304, *1305, and the new allele described here.
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PMID:DR6 in Koreans. DR11 frequently acts as a recipient gene to create DR13 alleles. 830 Apr 8

We report here the DNA polymerase chain reaction sequence-specific oligonucleotide (PCR-SSO) typing of the HLA-DR B1, B3, B4, B5 and DQB1 loci for a sample of 103 Vietnamese Kinh from Hanoi, and compare their allele and haplotype frequencies to other East Asiatic and Oceanian populations studied during the 11th and 12th International HLA Workshops. The Kinh exhibit some very high-frequency alleles both at DRB1 (1202, which has been confirmed by DNA sequencing, and 0901) and DQB1 (0301, 03032, 0501) loci, which make them one of the most homogeneous population tested so far for HLA class II in East Asia. Three haplotypes account for almost 50% of the total haplotype frequencies in the Vietnamese. The most frequent haplotype is HLA-DRB1*1202-DRB3*0301-DQB1*0301 (28%), which is also predominant in Southern Chinese, Micronesians and Javanese. On the other hand, DRB1*1201 (frequent in the Pacific) is virtually absent in the Vietnamese. The second most frequent haplotype is DRB1*0901-DRB4*01011-DQB1*03032 (14%), which is also commonly observed in Chinese populations from different origins, but with a different accessory chain (DRB4*0301) in most ethnic groups. Genetic distances computed for a set of Asiatic and Oceanian populations tested for DRB1 and DQB1 and their significance indicate that the Vietnamese are close to the Thai, and to the Chinese from different locations. These results, which are in agreement with archaeological and linguistic evidence, contribute to a better understanding of the origin of the Vietnamese population, which has until now not been clear.
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PMID:HLA-DR and -DQB1 DNA polymorphisms in a Vietnamese Kinh population from Hanoi. 944 2

Steroid-sensitive nephrotic syndrome (SSNS) of children has been associated with several HLA-DR and DQ alleles. To investigate this association in Egyptian children, 27 patients with SSNS were typed for HLA-DRB1 and DQB1 alleles using DNA polymerase chain-reverse hybridization technique. The results were compared with 121 healthy subjects for HLA-DRB1 and 59 subjects for DQB1 alleles. We found that: (1) patients have higher frequencies of both DQB1 *0601 (81.5% vs. 10.2% in controls, Pc=0.0001) and DRB1 *01 (44.4% vs. 3.3% in controls, Pc=0.00003). Their relative risks are significantly high [38.9, confidence interval (CI)=10.7-140.7, and 23.4, CI=6.7-81.9, respectively]; (2) the frequency of DRB1 *11 alleles was low in SSNS patients (3.75% vs. 32.2% in controls), but was not significant when P was corrected (P=0.005, Pc=NS). These findings suggest that DQB1 *0601 and DRBI *01 or closely associated unknown genes confer susceptibility to SSNS. However, further studies with larger numbers of patients are needed.
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PMID:HLA-DQB1 and DRB1 alleles in Egyptian children with steroid-sensitive nephrotic syndrome. 963 45

Background: Many genetic loci exhibit substantial heterogeneity: the human leukocyte antigen (HLA) DRB loci include 139 alleles and the cystic fibrosis transmembrane regulator gene more than 500 known mutations. Identification of alleles at these loci is cumbersome with typical molecular diagnostic methods such as hybridization assays or restriction enzyme analysis. Direct DNA sequencing of polymerase chain reaction (PCR) products is a general approach to complex loci that allows detection of any allele within the nucleotide sequence analyzed. However, direct DNA sequence-based unambiguous identification of heterozygous nucleotide positions using PCR templates is a challenging problem. Methods and Results: The ability of direct DNA sequencing methods to accurately identify HLA DRB alleles was assessed. The authors evaluated the performance of modified T7 and Taq DNA polymerases in isothermal and thermal cycle sequencing of PCR products derived from HLA DRB genes in 235 individuals who were potential donors or recipients of bone marrow transplants. The uniformity of peak intensity and ability to identify heterozygous nucleotide positions was similar when either AmpliTaq FS- or Sequenase DNA polymerase-derived electropherograms were prepared. The modified Taq DNA polymerase allowed the use of unpurified, double-stranded PCR templates. Furthermore, this enzyme could be used in less laborious, less costly cycle sequencing assays coupled with automated fluorescent detection methodology. Direct sequencing performed with either enzyme allowed unambiguous identification of DRB1 alleles, resolution of difficult heterozygous combinations, and recognition of new alleles. Conclusions: The direct DNA sequencing methods employed here for HLA allele identification are relatively efficient and semiautomated, and may be reasonably considered as a general approach to other complex molecular diagnostic problems, especially when coupled to simplified sequencing chemistries allowing cycle sequencing.
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PMID:Strategies for Unambiguous Detection of Allelic Heterozygosity via Direct DNA Sequencing of PCR Products: Application to the HLA DRB1 Locus. 1033 Feb 4

Reliable, high-resolution genotyping of human leukocyte antigen (HLA) polymorphisms is often compromised by DNA samples of suboptimal quality or limited quantity. We tested the feasibility of molecular typing for variants at HLA and neighboring loci using whole genome amplification (WGA) strategy facilitated by the Phi29 DNA polymerase. With little (5-100 ng) starting genomic DNA of varying quality and source materials, WGA was deemed successful in 167 of 169 DNA from 47 cell lines, 100 European Americans, and 22 native Africans. The Phi29-processed DNA provided adequate templates for polymerase chain reaction (PCR)-based analyses of several HLA (A, B, C, DRB1, and DQB1) and related loci (HFE, MICA, and 10 microsatellites) in the 6p24.3-6p21.3 region, with PCR amplicons ranging from 92 to 2200 bp. Five different genotyping techniques resolved and confirmed 364 genotypes when both original and Phi29-processed DNA worked in PCRs. General population genetic analyses provided additional evidence that WGA may represent a reliable and simple approach to securing ample genomic DNA for typing HLA, MICA, and related variants.
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PMID:Molecular typing of human leukocyte antigen and related polymorphisms following whole genome amplification. 1530 10

The association between HLA class II antigens and childhood primary nephrotic syndrome has been reported in different populations. To investigate this association in Egyptian children, DRB1 alleles were typed by DNA polymerase chain reverse hybridization in 20 frequent relapsers/steroid-dependent and 14 steroid-resistant children with minimal change nephrotic syndrome (MCNS) and 121 unrelated healthy controls from the northern part of Egypt. The strength of the association was expressed as the relative risk (RR) estimated by the odds ratio. The DRBI*07011 allele frequency was significantly higher among patients than controls (78.9% vs. 16%, Pc <0.001). The etiological fraction (EF) was high at 0.75 [RR=20.1, confidence interval (CI)=6.0-66.7]. Similarly, patients with steroid-resistant MCNS had a higher frequency of the DRBI*07011 allele than controls (64.3% vs. 16.5%, P c<0.001). The EF was high at 0.57 (RR=9.6, CI 2.9-31.7). In the whole group of patients the frequency of DRBI*11 alleles was low compared with controls (11.4% vs. 32.2%, P =0.02), but was not significant when P was corrected. In conclusion, the DRBI*07011 allele confers susceptibility to a frequently relapsing and steroid-dependent or steroid-resistant course of childhood MCNS. These patterns of the disease seem to have the same immunogenetic components.
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PMID:HLA alleles in frequently relapsing steroid-dependent and -resistant nephrotic syndrome in Egyptian children. 1562 17