WT1基因增强子构建位点对WT1基因启动子转录活性的影响

目的：以WT1基因启动子和增强子的功能片段为研究对象，探讨增强子构建在质粒的不同位点对基因启动子转录活性的影响。方法: 利用基因重组技术将WT1基因增强子的功能片段分别插入在已含有WT1基因启动子的质粒，pEWP的不同位点（MCS中的BamH I、EGFP 终止密码后的Not I和SV40polyA位点后的AflⅡ）中，将重组质粒转染慢粒白血病红白急变细胞株K562细胞、乳腺癌细胞株MCF-7细胞和人类胚胎肾转化细胞株293细胞，通过检测转基因细胞中EGFP的平均荧光强度来评估增强子对启动子的转录促进作用。结果: 通过基因重组技术分别构建了含有WT1基因启动子的载体，即pEWP，和含有WT1基因启动子和增强子的载体，即pEWPE、pEWPD和pEWPA。流式细胞仪检测EGFP的平均荧光强度，发现pEWPA在293细胞和K562细胞中能够增强WT1启动子的转录活性，而pEWPE和pEWPD则无增强作用。3者均不能在MCF7细胞中增强WT1启动子的转录活性。结论: SV40polyA位点后插入增强子能够有效地增强启动子的转录活性，且具有细胞特异性。     

Population differences in DNA sequence variation and linkage disequilibrium at the PON1 gene

Polymorphisms of the promoter region (?108C/T) and the coding region (192Q/R) of the paraoxonase 1 gene (PON1) showed differences in association with cardiovascular disease risk in various populations. To characterize the genetic variation underlying these important polymorphisms, we examined DNA sequence variation both in a 1.3‐kb promoter region 16.5 kb from codon 192, and in a 1.7‐kb region centered on the 192Q/R polymorphic site of the coding region of PON1, in 30 Africans, 30 Europeans and 64 Japanese. We found 10 polymorphic sites and 11 haplotypes in the 1.3‐kb promoter region and 10 biallelic polymorphic sites and 10 haplotypes in the 1.7‐kb region. From the PON1 sequences of chimpanzees and an orangutan, the ancestral type of codon 192 was found to be R. The number of pairs of polymorphic sites between the promoter and 1.7‐kb regions that were in significant linkage disequilibrium was much higher in a Japanese population than in African and European populations. In addition, the pairs of polymorphic sites in linkage disequilibrium differed among the three populations. These results suggest that some of the population differences in association with risk for coronary heart disease can be explained by population differences in haplotype frequency of PON1 haplotypes.     

The Potential Role of PTPN-22 C1858T Gene Polymorphism in the Pathogenesis of Type 1 Diabetes in Saudi Population

Background: Recent investigations have reported an association between protein tyrosine phosphatase non-receptor type-22 (PTPN-22) gene polymorphism and susceptibility to the development of type 1 diabetes (T1D) in some populations and not in others. In this study, we aimed to investigate the association of PTPN-22 C1858T polymorphism with T1D in Saudi children.

Methods: A cohort of 372 type 1 diabetic children and 372 diabetes-free subjects was enrolled in the current investigation. The PTPN-22 C1858T polymorphism was identified using the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method.

Results: Our data showed that the frequency of CT and TT genotypes of PTPN-22 C1858T was higher in T1D children (17.7% and 4.3%, respectively) compared to healthy controls (4.8% and 1.6%, respectively), and both genotypes were statistically associated with T1D patients (OR = 4.4, 95% CI: 2.55–7.58, p < 0.001; and OR = 3.2, 95% CI: 1.23–8.28, p = 0.017, respectively). Moreover, the 1858T allele was significantly associated with T1D patients compared to the C allele (OR = 3.2, 95% CI: 1.59–6.88, p < 0.001). In addition, the T allele was significantly associated with elevated levels of HbA1c, anti-GAD, and anti-insulin antibodies (p < 0.001) and a lower concentration of C-peptide (p < 0.001) in T1D children.

Conclusion: The data presented here suggests that the T allele of PTPN-22 C1858T polymorphism might be a risk factor for T1D development in Saudi children.     

Immunohistochemical localization of WT1 in epithelial salivary tumors

The subcellular localization of WT1 is controversial and has received little attention in the epithelial tumors of salivary glands. Paraffin-embedded, surgical specimens from 80 salivary tumors were investigated by immunohistochemistry using a monoclonal, anti-WT1 antibody (6F-H2, Dako). Immunostaining was seen in 14/14 pleomorphic adenomas (PAs), 6/6 myoepitheliomas, 4/4 basal cell adenomas, 4/4 canalicular adenomas, 0/7 Warthin tumors, 0/1 oncocytoma, 1/6 acinic cell carcinomas (Cas), 0/11 mucoepidemoid Cas, 1/11 adenoid cystic Cas, 11/12 polymorphous low-grade adenocarcinomas (PLGAs), 1/2 Ca ex PA, 0/1 salivary duct Ca and 0/1 clear cell adenocarcinoma. Stained-cell subpopulations up to 90% were not uncommon in the benign tumors. Up to 80% of cells in PLGA could be stained. Staining was weak to intense and confined to the cytoplasm of preferentially non-luminal or adjacent to stroma cells. One adenoid cystic Ca showed nuclear staining. The results suggest that WT1 is often highly expressed in benign non-oncocytic salivary tumors whereas the malignant tumors show decreased expression, the exception being PLGA. The expression is usually cytoplasmic and associated with non-luminal cells. PLGA immunoreactivities could be useful in histological differential diagnosis.     

Ancient,highly polymorphic human major histocompatibility complex DQA1 intron sequences

A 438 basepair intron 1 sequence adjacent to exon 2 in the human major histocompatibility complex DQA1 gene defined 16 allelic variants in 69 individuals from wide ethnic backgrounds. In contrast, the most variable coding region spanned by the 247 basepair exon 2 defined 11 allelic variants. Our phylogenetic human intron 1 tree derived by the Bootstrap algorithm reflects the same relative allelic relationships as the reported DQA1 exon 2 tree [Gyllensten and Erlich, Hum Immunol 36:1–10, 1989]. Thus 3′ DQA1 intron 1 and exon 2 have cosegregated since divergence of the human races. Comparison of human alleles to a Rhesus monkey DQA1 first intron sequence found only 10 nucleotide substitutions unique to Rhesus, with the other 428 positions (98%) found in at least one human allele. This high degree of homology reflects the evolutionary stability of intron sequences since these two species diverged over 20 million years ago. Because more intron 1 alleles exist than exon 2 alleles, these polymorphic introns can be used to improve tissue typing for transplantation, paternity testing, and forensics and to derive more complete phylogenetic trees. These results suggest that introns represent a previously underutilized polymorphic resource. © 1994 Wiley-Liss, Inc.     

A novelAvaI polymorphism within exon 5 of the rhodopsin gene

Summary We identified a novelAvaI polymorphism within 3 noncoding region within exon 5 of the human rhodopsin gene and determined the allele frequency in a Japanese population. The polymorphism was found to be due to A/G transversion at nucleotide 5510 of the gene.     

Infrequent mutation of the WT1 gene in 77 Wilms' tumors

Homozygous deletions in Wilms' tumor DNA have been a key step in the identification and isolation of the WT1 gene. Several additional loci are also postulated to contribute to Wilms' tumor formation. To assess the frequency of WT1 alterations we have analyzed the WT1 locus in a panel of 77 Wilms' tumors. Eight tumors showed evidence for large deletions of several hundred or thousand kilobasepairs of DNA, some of which were also cytogenetically detected. Additional intragenic mutations were detected using more sensitive SSCP analyses to scan all 10 WTl exons. Most of these result in premature stop codons or missense mutations that inactivate the remaining WTl allele. The overall frequency of WTl alterations detected with these methods is less than 15%. While some mutations may not be detectable with the methods employed, our results suggest that direct alterations of the WTl gene are present in only a small fraction of Wilms' tumors. Thus, mutations at other Wilms' tumor loci or disturbance of interactions between these genes likely play an important role in Wilms' tumor development. © 1994 Wiley-Liss, Inc.     

ERCC1 intron 1 was associated with breast cancer risk

Introduction

There are numerous studies addressing associations of polymorphisms in DNA repair genes and cancer risks because accurate and efficient DNA repair is crucial to genomic integrity and fidelity. ERCC1 is important in DNA nucleotide excision repair.

Material and methods

We genotyped constitutive variants of ERCC1 in approximately 300 adults with breast adenocarcinoma and 126 controls of Iranian women. In total, 426 Iranian sporadic breast cancer affected women compared to the control group were studied by PCR-RFLP for ERCC1 variant.

Results

The genotype ERCC1 TT has the highest frequency in both groups (36.6 in patients and 8.5 in controls). The genotype ERCC1 was the most important risk factor in our population [GG/AA odds ratio: 0.692, 95% confidence interval (CI): 0.4-1.199, p = 0.188; GG/AG odds ratio: 3.333, 95% CI: 1.917-5.795, p = 0.001; AA/AG odds ratio: 0.208, 95% CI: 0.124-0.348, p = 0.342].

Conclusions

Our patients was associated with breast cancer risk.     

Comparison of insertion rate of L1 retroposon into intron 30 of the neurofibromatosis type 1 gene in seven Asian and Pacific populations

Summary The allele frequency of a L1 retroposon insertion into intron 30 of the neurofibromatosis type 1 (NF1) gene was determined by analyzing amplified fragment lengths in seven Asian or Pacific populations; namely, Japanese, Chinese, Indian, Malay, Filipino, Indonesian and New Guinean. Nearly 100 chromosomes from each group were analyzed. The presence of the L1 insertion was identified by the appearance of an abnormally large PCR-amplified product. The insertion frequency varied from 0.45 to 0.75, depending on the population group. Malay and Indonesia populations were found to have the highest insertion frequencies (0.75 and 0.72, respectively), while the wild-type genotype was more prevalent in Indians. The lowest insertion frequency (0.45), observed in Indians, was nearest to that reported in Westerners (0.35). The different L1 insertion frequencies found in Asian and Pacific groups reflect a major divergence in these human populations. Japanese and Chinese populations showed the highest heterozygosity (0.50), suggesting the usefulness of this polymorphism in linkage analysis in these populations.     

Allele frequency ofHinfI restriction fragment length polymorphism (RFLP) and dinucleotide repeat polymorphism in the wilms tumor gene (WT1) among the Japanese

The frequency ofHinfI RFLP and dinucleotide (CA) repeat polymorphism for theWT1 located to chromosome 11p13 among the Japanese were estimated. Each polymorphism showed high frequency of heterozygosity and segregated independently.     

白细胞介素-1基因多态性与原发性高血压关联

目的研究白细胞介素-1(IL-1)基因多态性与原发性高血压的相关关系。方法采用聚合酶链反应-限制性片段长度多态性(PCR-RFLP)技术,检测150例原发性高血压患者和160例健康对照者IL-1基因多态性。结果IL-1α基因-889C/T多态性在两组人群中的分布差异显著(P<0.05);等位基因频率的相对风险分析发现,T等位基因携带者患原发性高血压的风险是C等位基因的2.102倍(OR=2.102,95%CI:1.231~3.590),携带CT+TT基因型的原发性高血压患者收缩压水平显著高于CC基因型者[(168.9±19.8)mmHg比较(160.2±18.9)mmHg],(P<0.05)。结论IL-1α基因-889C/T多态性与原发性高血压的发病具有相关性,其中T等位基因可能是原发性高血压发病的遗传易感基因,携带T等位基因的个体可能通过促进收缩压的升高进而增加了原发性高血压的发病风险。     

蒙族和汉族人群 CYP1A1基因MspⅠ位点的多态性

目的研究内蒙古地区蒙族和汉族人群CYP1A1基因Msp Ⅰ位点的多态性。方法应用聚合酶链反应．限制性片段长度多态技术对无血缘关系的80名蒙族和120名汉族个体的基因型进行分析。结果内蒙古地区蒙族和汉族人群CYP1A1基因wt／wt、wt／vt和vt/vt 3种基因型的频率分布分别是：蒙族35．0％、48．7％、16．3％和汉族33．3％、52．5％、14．2％。两者之间经X^2检验差异无统计学意义（P〉0．05）。结论内蒙古地区蒙族和汉族人群CYP1A1 基因Msp Ⅰ的基因型频率分布无明显差异。     

Association between genetic variation at the APO AI-CIII-AIV gene cluster and familial combined hyperlipidaemia

By using chemical cleavage mismatch analysis and the single strand conformation polymorphism technique, DNA fragments of the apo CIII gene, including the 5′ flanking region and all the exons, were screened for sequence changes underlying the observed association between familial combined hyperlipidaemia (FCHL) and the apo AI-CIII-AIV gene cluster in affected individuals from eight FCHL families. A C₁₁₀₀-T transition in the wobble position of codon 14 in exon 3 and a T₃₂₀₆-G transversion in the non-translated region of exon 4 were identified, occurring in four and all probands, respectively. Using these variants and the G_{_75}-A transition in the apo AI promoter, co-segregation of the gene cluster with hyperlipidaemia could be excluded in all eight families (lod score -∞ at θ=0). No support for co-segregation was obtained using the affected pedigree member method of linkage analysis (overall T=–0.77 for f (p)=1√p). The frequencies of T₁₁₀₀ and G₃₂₀₆ in a group of 55 patients with combined hyperlipidaemia were 0.35 and 0.52, respectively, which were significantly higher compared to 360 controls (0.21, p<0.01 and 0.35 p<0.005 respectively). In patients homozygous for the T₁₁₀₀ allele, levels of plasma triglyceride were 2.5-fold higher (868 mg/dl) than those homozygous for the C₁₁₀₀ allele (337 mg/dl), while patients heterozygous for the polymorphism had intermediate values (443 mg/dl) (p<0.01). A similar association was seen in controls (p<0.04). The three polymorphisms studied were in strong linkage disequilibrium in both the group of CHL patients and the unrelated individuals. This study confirms the association between common variation in the gene cluster and differences in plasma lipid levels in the general population and in patients with combined hyperlipidaemia, but fails to confirm co-segregation with FCHL, suggesting the role of other genetic or environmental factors in the aetiology of FCHL.     

NURR1基因多态性与帕金森病的关联研究

目的 了解NURR1基因多态性与四川地区散发性帕金森病之间的相关性.方法 采用病例-对照研究,应用聚合酶链反应、等位基因特异性、限制性片段长度多态性对四川地区汉族人群241例帕金森病患者和236名正常对照NURR1基冈启动子区的c.-2922(C)2-3及第6内含子的ⅣS6+18imG多态位点进行关联分析.结果 IVS6+18insG位点帕金森病组3G/3G,3G/2G,2G/2G基因型频率与对照组相比差异无统计学意义(X2=3.733,P=0.155).进一步按发病年龄分层后发现,50岁以前发病的帕金森病患者基因型频率与对照组之间差异有统计学意义(X2=6.545,P=0.038).发病年龄＜50岁的帕金森病组患者3G/2G基因型频率显著高于对照组(54.12%vs 38.14%),并且与其他两组基因型合并相比差异有统计学意义(X2=6.537,P=0.011;OR=1.913,95%CI:1.159～3.158).c.-2922(C)2-3位点帕金森病组与对照组相比3C/3C,3C/2C及2C/2C基因型频率差异无统计学意义(P=0.766).结论 本研究结果提示NURR1基因ⅣS6+18insG多态可能与本组人群早发性帕金森病的遗传易感性相关;未发现c.-2922(C)2-3位点多态性与本组人群帕金森病的遗传易感性相关.     

Two single nucleotide polymorphisms of the hSNF5/INI1 gene

We found two single nucleotide polymorphisms at the hSNF5/INI1 gene located on 22q11.2, encoding a member of the chromatin-remodelling SWI/SNF multiprotein complexes. A guanine/adenine polymorphism at codon 299 in exon 7, and another guanine/adenine polymorphism at 39 bp upstream of exon 9 were identified. As the gene was recently identified as a tumor suppressor gene for malignant rhabdoid tumor, this polymorphism may be useful for the genetic study of susceptibility for human malignancies of various tissue origins. Received: March 19, 1999 / Accepted: April 16, 1999     

Two cases of isolated diffuse mesangial sclerosis with WT1 mutations

Here we report two cases of isolated diffuse mesangial sclerosis (IDMS) with early onset end-stage renal failure. These female patients did not show abnormalities of the gonads or external genitalia. Direct sequencing of WT1 PCR products from genomic DNA identified WT1 mutations in exons 8 (366 Arg>His) and 9 (396 Asp>Tyr). These mutations have been reported previously in association with Denys-Drash syndrome (DDS) with early onset renal failure. Therefore we suggest that, at least in part, IDMS is a variant of DDS and that investigations for the WT1 mutations should be performed in IDMS patients. In cases with identified WT1 mutations, the same attention to tumor development should be required as in DDS patients, and karyotyping and serial abdominal ultrasonograms to evaluate the gonads and kidney are warranted.