HMGB1对HTLV-1病毒Tax蛋白表达的T细胞中NF-κB活性的影响

目的:构建人高迁移率组蛋白1(high mobility group box-1,HMGB1)的真核表达载体,转入TaxP及TaxN细胞进行表达,并研究其对Tax蛋白表达的T细胞中NF-κB活性的影响。方法:用RT-PCR方法扩增人T淋巴细胞系Jurkat细胞中HMGB1的cDNA,连接于真核表达载体pcDNA3.0;将pcDNA3.0-HMGB1转染TaxP及TaxN细胞,48小时后检测RT-PCR检测HMGB1和Tax mRNA的表达,HMGB1及p65蛋白的表达;将pcDNA3.0-HMGB1和NF-κB报告基因共转染TaxP及TaxN细胞48小时后检测荧光素酶活性。结果:成功构建了重组表达质粒pcDNA3.0-HMGB1;Tax可以促进HMGB1mRNA和蛋白的表达,HMGB1可以促进p65mRNA和蛋白的表达,并能上调NF-κB活性。结论:HMGB1能协同Tax蛋白激活NF-kB。     

HMGB1调控区Jurkat稳定细胞株的构建

目的:构建不同长度的高迁移率族蛋白1(HMGB1)基因调控序列的真核表达载体及其稳定表达的Jurkat细胞株,为研究HMGB1基因在白血病发病机制建立基础。方法:以Jurkat细胞基因组为模板,PCR扩增3’端固定的8个不同长度的HMGB1调控基因(-83 bp～+83 bp、-383 bp～+83 bp、-504 bp～+83 bp、-688 bp～+83 bp、-975 bp～+83 bp、-1 163 bp～+83 bp、-1 327 bp～+83 bp、-1 520 bp～+83 bp),均将其连入pMD18-T载体,并转化大肠杆菌DH5a。对氨苄青霉素筛选的阳性克隆进行扩增、质粒抽提,应用KpnⅠ/HindⅢ、BamHⅠ/HindⅢ双酶切鉴定和DNA测序获得序列正确的阳性克隆,然后再经酶切连入pGL3-neo-luc质粒,成功构建HMGB1基因调控序列报告基因pGL3-HMGB1-luc(按由短至长顺序依次命名为1～8号质粒)。利用脂质体介导的方法将不同长度的pGL3-HMGB1-luc质粒和pGL3-neo-luc质粒分别转染至Jurkat细胞,48小时后加入终浓度600μg/ml的G418进行药物加压筛选,20天后得到有效转染pGL3-HMGB1-luc及pGL3-neo-luc载体的Jurkat细胞株(按有无HMGB1调控基因及其由短至长顺序,依次命名为NEO细胞和1～8号细胞)。通过检测荧光素酶活性,验证构建的Jurkat稳定细胞株(Jurkat-HMGB1)。结果:HMGB1调控基因成功插入到pGL3-neo-luc的XhoⅠ和HindⅢ位点之间构建出3号质粒;HMGB1调控序列1016 bp定向克隆至3号质粒的KpnⅠ和XhoⅠ位点之间,成功构建出8号质粒;将166、466、771、1 058、1 246、1 410 bp长度的HMGB1调控基因定向克隆至3号质粒的KpnⅠ和HindⅢ位点之间,分别构建出1号、2号、4号、5号、6号、7号质粒。8个质粒均经KpnⅠ/HindⅢ、BamHⅠ/HindⅢ双酶切,电泳显示条带与扩增的HMGB1调控序列长度一致。HMGB1-T载体的DNA测序结果与NCBI提供序列完全匹配。成功构建了不同长度的3’端固定的pGL3-HMGB1-luc报告基因。pGL3-neo-luc和pGL3-HMGB1-luc稳定转染至Jurkat细胞后,成功构建了NEO细胞和稳定细胞株HJ1～8,其荧光素酶发光值分别为:123、151 288、136 057、110 623、100 874、214 523、147 597、161 348、145 490。结论:构建的HMGB1调控序列报告基因和HJ稳定细胞株为找寻有意义的HMGB1调控区域,以及后期研究HMGB1基因在成人T淋巴细胞白血病中的发病机制奠定了基础。     

HTLV-1病毒Tax蛋白对T淋巴细胞DcR3基因表达的影响

目的 探讨HTLV-1病毒Tax蛋白对T淋巴细胞DcR3基因表达的影响.方法 构建pGL3-DcR3-luc( -1010 bp- +114 bp)荧光素酶报告基因;利用脂质体介导的方法将pGL3 -DcR3 -luc转染到MT-2、TaxP、Jurkat细胞中,48h后检测DcR3荧光素酶报告基因的活性;利用脂质体介导的方法将梯度剂量的pCMV -Tax转染入Jurkat细胞,48 h后提RNA逆转录,real-time PCR检测DcR3 mRNA 的表达的变化;选用流式细胞技术检测MT-2、TaxP、Jurkat细胞表面DcR3蛋白的表达.结果 成功构建DcR3基因调控序列荧光素酶报告基因pGL3-DcR3-luc;荧光素酶活性的检测显示,与对照组相比,MT2细胞荧光素酶活性升高了32.07± 12.43倍,TaxP细胞荧光素酶活性升高了13.27±4.04倍,Jurkat细胞荧光素酶活性升高了1.26±0.49倍.与Jurkat细胞相比,MT2细胞和TaxP细胞的相对荧光素酶活性明显升高(P＜0.01);Real-time PCR结果显示,4组Ct内参/Ct目的基因的值依次是0.40±0.02、0.44±0.01、0.47±0.02、0.53±0.02; DcR3 mRNA的表达与转染pCMV-Tax存在着剂量依赖性(P＜0.05).流式细胞技术检测,MT2和TaxP细胞实验组DcR3蛋白的表达较对照组Jurkat细胞表达的高(P＜0.05).MT2细胞的结果是33.1 ±9.9,TaxP细胞的结果是35.1 ±4.8,Jurkat细胞的结果是16.9±2.3.结论 Tax蛋白能够促进DcR3基因在T细胞中的表达.     

T细胞白血病病毒1型Tax蛋白阳性细胞中早期生长反应基因-1对NF-κB活性的影响

目的 观察人T细胞白血病病毒1型(HTLV-1)的Tax蛋白阳性细胞中早期生长反应基因-1(EGR-1)与NF-κB的关系.方法 RT-PCR扩增MT2细胞中EGR-1的cDNA全长,连接于真核表达载体pcDNA3.0;用脂质体介导的方法将pcDNA3.0-EGR-1转染TaxP/TaxN细胞,48 h后PCR检测EGR-1和p65 mRNA的表达,Western blot检测EGR-1及p65蛋白的表达;将pcDNA3.0-EGR-1和NF-κB报告基因共转染TaxP及TaxN细胞48 h后检测荧光素酶活性.结果 成功构建了重组表达质粒pcDNA3.0-EGR-1,Tax可以促进EGR-1 mRNA和蛋白的表达;EGR-1可以促进TaxP细胞p65 mRNA和蛋白的表达,上调NF-κB活性.结论 EGR-1可能通过促进NF-κB活化参与成人T淋巴细胞白血病(adult T-cell leukemia,ATL)的发病.

Abstract：

Objective To research the relation of early growth response gene-1(EGR-1) and NF-κB in human T-cell leukemia virus type 1(HTLV-1) Tax protein positive cells. Methods RT-PCR was used to amplify the aimed segments EGR-1 cDNA which was then inserted into an eukaryotic expression plasmid pcDNA3.0 to construct pcDNA3.0-EGR-1. The constructed plasmid was transfected into TaxN and TaxP cells by Tfx-50-mediated transfer method, the expression levels of EGR-1, p65 and Tax mRNA in transfected cells were assay by RT-PCR after 48 h post-transfection, the proteins of EGR-1 and p65 were detected by Western blot after 48 h post-transfection too. The constructed plasmid and pNF-κB-luc reporter gene plasmid was co-transfected into TaxN and TaxP cells by Tfx-50-mediated transfer method, and the activity of luciferase was assay after 48 h post-transfection. Results The results showed that the eukaryotic expression plasmid pcDNA3.0-EGR-1 was successfully constructed. The mRNA and protein expression of EGR-1 could be promoted significantly by Tax. EGR-1 can promote the mRNA and protein expressions of p65 in TaxP cells, the activity of NF-κB was up-regulated by EGR-1 too. Conclusion EGR-1 maybe involve in adult T-cell leukemia(ATL) by increasing the activation of NF-κB.     

人BAFF-R基因启动子活性的初步研究

目的以B淋巴细胞刺激因子受体BAFF-R基因5'上游区序列为研究对象,初步鉴定、分析该基因的启动子所在区域。方法克隆BAFF-R基因5'侧翼区1823 bp序列,构建8个含有不同长度启动子序列的荧光素酶报告基因表达质粒pGL3-B1～B8,将这8个序列缺失重组质粒与psv-β-gal质粒共转染细胞,检测荧光素酶的相对活性,确定启动子所在区域。结果8个重组质粒中pGL3-B2、pGL3-B3、pGL3-B5、pGL3-B6启动子的活性较低;pGL3-B7启动子的活性最强,pGL3-B8启动子活性最低。结论BAFF-R基因5'端-288～-430、-712～-868和-1420～-1562三个区段可能存在转录沉默子元件,-617～-712和-1277～-1420区段存在转录增强子元件,BAFF-R基因的核心启动子可能位于-1420～+261区域。     

通路抑制剂对Tax诱导的Bcl-3的影响及其在NF-κB激活中作用的研究

目的:通过研究不同通路的抑制剂在TaxP细胞(稳定表达Tax的Jurkat亚细胞系)中对Bcl-3(Human B-cellleukemia protein 3)表达的影响和shRNA Bcl-3对NF-κB转录激活作用的影响,探讨Tax阳性细胞中调控Bcl-3的通路及Bcl-3在NF-κB通路中的作用。方法:将TaxP细胞分别用NF-κB(Nuclear factor-κB)抑制剂、GSK(Glycogen synthase kinase)抑制剂和蛋白酶抑制剂处理后,Western blot检测Bcl-3蛋白的表达情况;将Bcl-3的shRNA质粒转入TaxP细胞中,RT-PCR检测Bcl-3mRNA的表达抑制情况;共转染Bcl-3的shRNA和pNF-κB-luc质粒至Jurkat和TaxP细胞中,检测抑制Bcl-3表达后对NF-κB转录活性的影响。结果:Bcl-3的表达不受GSK抑制剂的影响,但在蛋白酶抑制后有明显的升高;RT-PCR的结果表明,在转染Bcl-3 shRNA质粒后,Bcl-3的mRNA表达有明显的下降,荧光素酶活性结果显示Bcl-3在Jurkat和TaxP细胞中被抑制后NF-κB的转录活性明显下降(P0.05)。结论:Tax诱导的Bcl-3表达不依赖于GSK通路,而NF-κB通路参与了Bcl-3的调控,说明Bcl-3在NF-κB的激活中发挥着促进作用。     

SPA基因启动子的克隆及转录靶向活性分析

目的：克隆大鼠肺表面活性蛋白A（SPA）基因启动子并构建该启动子的荧光报告系统,探讨该启动子的活性及转录靶向性，为进一步研究SPA 基因的表达调控机制和探讨靶向性基因治疗奠定基础。方法:①从GenBank中获取大鼠SPA 基因序列，对其上游基因组序列进行计算机生物信息学分析，推断其上游序列约163bp的区域具有启动子功能。②利用PCR技术扩增SPA 基因上游启动子序列,将其亚克隆入pGL3-basic 中,构建pGL3-SPA 质粒，将其亚克隆于pGL3-control 中，构建pGL3-SPA-enhancer 质粒。③将构建pGL3-SPA质粒、pGL3-SPA-enhancer 质粒、pGL3-control质粒和pGL3-basic 质粒分别与内参质粒pRL-TK共转染入A549细胞和H441细胞, 用双荧光素酶报告系统检测该质粒在两种细胞中的荧光素酶活性表达。 结果:酶切及测序结果均证实成功克隆了SPA基因启动子序列,并已将该序列正确插入到荧光素酶报告基因系列载体中。重组的pGL3-SPA-enhancer 质粒、pGL3-SPA质粒转染H441 细胞后可以检测到荧光素酶的高表达。结论:成功构建了含有SPA 基因启动子序列的荧光素酶基因报告系统,证实了它在高表达SPA蛋白的细胞中有较高的转录活性， 为下一步研究SPA 基因功能及其转录调控以及探讨基因治疗的靶向性奠定了基础。     

c-Jun对硫氧还蛋白还原酶1启动子转录的调控作用

目的: 探讨转录因子激活剂蛋白-1(activator protein-1,AP-1)家族成员c-Jun对硫氧还蛋白还原酶1(thioredoxin reductase 1, TrxR1 )启动子转录的调控作用。方法: 利用生物信息学技术分析调控 TrxR1 启动子区域的转录因子,构建 TrxR1 启动子区域一系列截短的萤光素酶报告基因载体,将含c-Jun的真核表达载体pcDNA3.1(+)-c-Jun和含有 TrxR1 启动子的萤光素酶报告基因载体共转染人胚肾HEK293细胞和鼠心肌H9c2细胞,检测转染细胞中萤光素酶活性。应用定点突变技术针对 TrxR1 启动子区域AP-1的可能结合位点进行突变,与c-Jun的真核表达载体共转染上述2种细胞,检测各组萤光素酶活性。利用染色质免疫共沉淀(ChIP),分析c-Jun与 TrxR1 启动子区域的AP-1结合位点结合情况。结果: 酶切及测序结果表明,获得的3个不同长度的 TrxR1 启动子克隆与GenBank DNA序列数据库对比分析序列一致,且插入方向正确;此3种质粒都有明显的启动子活性,在人胚肾HEK293和鼠心肌H9c2细胞中转染pcDNA 3. 1(+)-c-Jun可以上调 TrxR1 启动子活性。突变AP-1结合位点,导致 TrxR1 启动子活性明显降低;ChIP结果显示c-Jun结合在 TrxR1 启动子区域的AP-1结合位点上。结论: 转录因子AP-1家族成员c-Jun可能通过与 TrxR1 基因启动子区域AP-1结合位点相结合,上调 TrxR1 基因的转录。     

细胞因子对T细胞生长激素基因表达的影响

目的 探讨各种细胞因子对T细胞生长激素（GH）基因表达的影响。方法 构建含人GH调控序列的荧光素酶报告基因质粒pGL2-GH-luc，然后转染入T淋巴细胞系Jurkat E6-1细胞中，在培养液中分别加入各种细胞因子。结果 生理浓度的IL－1β，TNF－β和IFN－γ，对Jurkat细胞中荧光素酶的表达具有抑制作用（P＜0．05）。结论 细胞因子参与了调节淋巴细胞GH基因的表达。     

HLA-DRB1, -DQA1, -DQB1, -DPA1 and -DPB1 genes in Japanese multiple sclerosis patients

Japanese MS patients and controls were examined for the distribution of HLA-DRB1, -DQA1, -DQB1, -DPA1 and -DPB1 alleles using in vitro amplification of genomic DNA and probing with sequence-specific oligonucleotides. No significant difference in frequency of the examined alleles was observed among the two groups. This is in contrast to Norwegian MS patients, where an association to a combination of certain DQA1 and DQB1 alleles has previously been demonstrated.     

NDE1 and NDEL1: Multimerisation,alternate splicing and DISC1 interaction

Nuclear Distribution Factor E Homolog 1 (NDE1) and NDE-Like 1 (NDEL1) are highly homologous mammalian proteins. However, whereas NDEL1 is well studied, there is remarkably little known about NDE1. We demonstrate the presence of multiple isoforms of both NDE1 and NDEL1 in the brain, showing that NDE1 binds directly to multiple isoforms of Disrupted in Schizophrenia 1 (DISC1), and to itself. We also show that NDE1 can complex with NDEL1. Together these results predict a high degree of complexity of DISC1-mediated regulation of neuronal activity.     

韩国人CYP450 1A1、CYP450 2E1和GSTM1、GSTT1、GSTP1基因座遗传多态性分析

目的 调查代谢相关的CYP4501A1、CYP4502E1和GSTM1、GSIT1、GSTP1基因座在韩国人群中的遗传多态性分布状况。方法 采用多重聚合酶链式反应、聚合酶链式反应-限制性片段长度多态性技术，分析300名韩国健康大学生的CYP1A1基因3′端限制性内切酶Msp Ⅰ位点、CYP2E1基因5′端转录调节区Pst Ⅰ位点和GSTM1、GSTT1缺失与存在、GSTP1基因第5外显子BsmA Ⅰ位点的基因型，计算基因型和基因频率。结果 CYP1A1基因型频率为ml／ml型39．7％、ml／m2型49．7％、m2／m2型10．7％，基因频率为ml 0．645、m2 0．355。CYP2E1基因型频率为cl／cl型66．7％、cl／c2型30％、c2／c2型3．3％，基因频率为C1 0．818、C2 0．182。GSTM1基因缺失型频率为53．3％。GSTT1基因缺失型频率为54．7％。GSTP1基因型频率为Ile／Ile型62％、Ile／Val型34．3％、VaL／Val型3．7％，基因频率为Ile 0．792、Val 0．208。基因分布符合Hardy-Weirtberg平衡定律。结论 韩国人CYP1A1、CYP2E1、GSTM1、GSTT1基因分布与我国人群较为相近，半数以上人缺乏GSTM1和GSTT1基因，纯合缺失型频率超过印度人的3倍。     

Rb1cc1 is critical for myoblast differentiation through Rb1 regulation

Rb1-inducible coiled-coil 1 (Rb1cc1) expressed at high levels is associated with the maturation of human embryonic musculoskeletal cells. To clarify the molecular role of Rb1cc1 in muscular differentiation, we investigated the expression of Rb1cc1 and other genes that regulate differentiation in murine embryonic tissues and in C2C12 myoblasts. We also evaluated the effects of RNA interference (RNAi)-mediated Rb1cc1 knockdown on C2C12 myoblast differentiation. After Rb1cc1, Rb1 and myosin heavy chain (Myhc) were expressed in mouse embryonic muscles. The synchronous expression of Rb1cc1 and Rb1 predicted Myhc expression during C2C12 myoblast differentiation. RNAi-mediated knockdown of Rb1cc1 led to Rb1 suppression, and C2C12 myoblasts failed to differentiate. These results indicated that Rb1cc1 is a potent regulator of the Rb1 pathway and a novel mediator that plays a crucial role in muscular differentiation. Rb1cc1 expression is, thus, a prerequisite for myogenic differentiation.     

Maternal genetic polymorphisms in CYP1A1, GSTM1 and GSTT1 and the risk of hypospadias

Hypospadias is one of the most common congenital anomalies. Increased exposure to environmental factors (endocrine-disrupting chemicals and smoking) or maternal endogenous estrogen may cause hypospadias because male sexual differentiation is dependent on normal androgen homeostasis. Moreover, interactions between genetic factors and cigarette smoking and other chemicals have been suggested. It has been demonstrated that the CYP1A1 metabolizes not only environmental chemicals but also estrogens, and glutathione-S-transferases (GSTs) are detoxification enzymes that protect cells from toxicants by conjugation with glutathione. In this study, to investigate the association of CYP1A1 (MspI), GSTM1 and GSTT1 polymorphisms with hypospadias, a case-control study of 31 case mothers who had boys with hypospadias and 64 control mothers was performed in Japan. These polymorphisms were investigated by PCR-based methods using DNA from peripheral lymphocytes. We found that the heterozygous CYP1A1 and heterozygous and homozygous CYP1A1 were less frequent in the case mothers than in the control mothers [adjusted odds ratio (OR)=0.17, 95% confidence interval (CI)=0.04-0.74, OR = 0.28, 95% CI = 0.08-0.97, respectively]. We found no effect of maternal smoking on the hypospadias risks among the gene polymorphisms. The results suggest that mothers with the CYP1A1 MspI variant allele may have a decreased risk for hypospadias.     

Circulatinglong non-coding RNA FEZF1-AS1 and AFAP1-AS1 serve as potential diagnostic biomarkers for gastric cancer

BackgroundGrowing evidence indicates that two long non-coding RNAs (lncRNAs), FEZ family zinc finger 1 antisense RNA 1 (FEZF1-AS1) and Actin filament associated protein 1 antisenseRNA1 (AFAP1-AS1), are highly expressed in different cancers, including gastric cancer (GC). However, the expression pattern and clinical utility of these two lncRNAs are still unknown.MethodsSerum expression levels of FEZF1-AS1 andAFAP1-AS1 were measured by quantitative real-time polymerase chain reaction (qRT-PCR). CEA and CA19-9 were detected by ARCHITET I2000 SR. Analyses were all performed using SPSS software version 20.0 (SPSS Inc., Chicago, USA). P < 0.05 was considered statistically significant.ResultsDetection of serum FEZF1-AS1 and AFAP1-AS1 showed both of them were up-regulated in GC patients compared with the normal controls (p < 0.0001), and high serum expression levels were correlated with tumor size, tumor-node-metastasis (TNM) stage and lymph node metastasis. Besides, the area under the ROC curve (AUC) demonstrated the two lncRNAs had higher diagnostic utility than CEA and CA19-9. Furthermore, when combined the two lncRNAs as a model, it yielded an AUC of 0.866, and the combination of the model, CEA and CA19-9 could observably improve diagnostic sensitivity to 95.5 %. What’s more, circulating FEZF1-AS1 and AFAP1-AS1 were significantly decreased after the GC patients underwent the operation (both p < 0.001).ConclusionOur study indicated that serum FEZF1-AS1 and AFAP1-AS1 had better sensitivity and efficiency for the diagnosis of GC and the combination of the two lncRNAs might be used as a potential prognostic indicator in GC.     

神经系统RNA结合蛋白Musashi1 RRM1的初步结晶

目的 对Musashi1发挥功能的 RRM1结构域进行结晶,得到可用来衍射的蛋白晶体,为之后的结构解析打基础。方法 通过构建Musashi1RRM1的原核表达载体,并在BL21中表达、纯化高纯度的蛋白质,通过筛选结晶体条件得到蛋白晶体。结果 通过系统筛选和优化晶体生长条件得到了蛋白晶体。结论 Musashi1 RRM1的蛋白晶体质量较好,满足蛋白晶体衍射和数据收集的要求。     

HIV-1 Nef stabilizes AP-1 on membranes without inducing ARF1-independent de novo attachment

HIV-1 Nef affects the trafficking of numerous cellular proteins to optimize viral replication and evade host defenses. The adaptor protein (AP) complexes, which form part of the cytoplasmic coat of endosomal vesicles, are key cellular co-factors for Nef. Nef binds these complexes and alters their physiologic cycle of attachment and release from membranes. Specifically, while AP-1 normally becomes cytosolic when attachment events are blocked by inhibition of the GTPase cycle of ADP-ribosylation factor-1 (ARF1), the complex remains membrane-associated in Nef-expressing cells. To investigate the mechanism of this effect, we used a permeabilized cell system to detect the de novo attachment of exogenous AP-1 to endosomal membranes. Nef did not mediate de novo attachment independently of ARF1, despite its ability to maintain the association of AP-1 with endosomal membranes when the activity of ARF1 was blocked. We conclude that Nef stabilizes AP complexes on endosomal membranes after ARF1-dependent attachment. This stabilization may facilitate coat formation and stimulate the trafficking of multiple cellular proteins.     

IL—1受体相关激酶—1和—2协同调控IL—1诱导的AP—1的活化

目的研究白介素 - 1受体相关激酶 - 1(IRAK- 1)和 IRAK- 2在白介素 - 1(IL - 1)诱导 AP- 1活化中的作用。方法L ipofectin介导反义 IRAK- 1寡核苷酸和反义 IRAK- 2寡核苷酸转染 Hep G2细胞。用逆转录 PCR法检测 IRAK - 1和 IRAK- 2m RNA表达水平 ;Western blot分析 IRAK- 1和 IRAK - 2蛋白表达水平。以 Sandwich EL ISA法检测 AP- 1的活化。结果反义IRAK- 1寡核苷酸和反义 IRAK- 2寡核苷酸通过抑制各自靶基因 m RNA和蛋白表达抑制 IL- 1诱导的 AP- 1活化 ;反义 IRAK-1寡核苷酸与反义 IRAK- 2寡核苷酸共转染 Hep G2细胞对 AP- 1的抑制作用较两者单独转染明显增强。结论 IRAK- 1和 I-RAK- 2在调控白介素 - 1诱导的 AP- 1活化时协同作用。     

Ah receptor, CYP1A1, CYP1A2 and CYP1B1 gene polymorphisms are not involved in the risk of recurrent pregnancy loss

The etiology of recurrent pregnancy loss (RPL) remains unclear, but it may be related to a possible genetic predisposition together with involvement of environmental factors. We examined the relation between RPL and polymorphisms in four genes, human aryl hydrocarbon (Ah) receptor, cytochrome P450 (CYP) 1A1, CYP1A2 and CYP1B1, which are involved in the metabolism of a wide range of environmental toxins and carcinogens. All cases and controls were women resident in Sapporo, Japan and the surrounding area. The Ah receptor, CYP1A1, CYP1A2 and CYP1B1 genotypes were assessed in 113 Japanese women with recurrent pregnancy loss (RPL) and 203 ethnically matched women experiencing at least one live birth and no spontaneous abortion (control). No significant differences in Ah receptor, CYP1A1, CYP1A2 and CYP1B1 genotype frequencies were found between the women with RPL and the controls [Ah receptor: Arg/Arg (reference); Arg/Lys and Lys/Lys, odds ratio (OR)=0.67; 95% confidence interval (CI)=0.40-1.11, CYP1A1: m1m1 (reference); m1m2 and m2m2, OR = 0.86; 95% CI = 0.53-1.40, CYP1A2: C/C and C/A (reference); A/A, OR = 1.16; 95% CI = 0.71-1.88, CYP1B1: Leu/Leu (reference); Leu/Val and Val/Val, OR = 1.18; 95% CI = 0.68-2.02]. The present study suggests that the Ah receptor, CYP1A1, CYP1A2 and CYP1B1 gene polymorphisms are not major genetic regulators in RPL.