非洲爪蟾GATA-1b中与GATA-1a的差异位点突变后的功能

非洲爪蟾GATA 1因子分为GATA 1a和GATA 1b两种亚型。与其他种类的GATA 1因子相类似 ,GATA 1是红细胞分化成熟所必需的因子之一。二种亚型在造血方面具有同样的作用 ,但只有xGATA 1b具有抑制神经发生的功能。比较二者的结构 ,发现二者的核酸和蛋白质结构虽然都非常相似 ,但并不完全一致。为探讨这些差异结构与功能之间的关系 ,我们对xGATA 1b中与xGATA 1a差异的Ser1 6 8和His1 6 9位点进行缺失突变 ,并定点突变Thr30 4和Thr359位点。之后将体外制备好的野生型或突变型xGATA 1bmRNA单独或与DN BRmRNA共同导入非洲爪蟾 2细胞胚胎内 ,利用动物帽系统分析突变体在神经发生和造血方面的功能。结果发现 ,Ser1 6 8和His1 6 9以及Thr359位点突变后 ,xGATA 1b再不能抑制DN BR诱导的神经发生 ;但所有突变都未影响xGATA 1b在造血方面的功能。由此 ,我们首次证实了Ser1 6 8和His1 6 9以及Thr359位点可能是导致xGATA 1b和xGATA 1a之间功能分离的结构基础之一。     

猪Mx1基因第14外显子多态性分析及新突变位点的 发现

采用PCR-RFLP方法对国内外7个猪种Mx1基因第14外显子的多态性进行分析, 共检测到3个等位基因, 6种基因型。其中杜洛克中仅存在AA基因型, 苏太猪中存在全部基因型, 只有在梅山猪和具有梅山猪血统的苏太猪中出现基因型BB。所有猪种中, 只有在地方猪种和培育猪种中出现等位基因B, 所有猪种除松辽黑猪外均以A为优势等位基因。卡方检验结果表明, 不同猪种间基因型分布差异较大, 梅山猪和松辽黑猪与其他所有猪种的基因型频率差异极显著(P＜0.01) , 苏太猪与除皮特兰猪外的所有猪种的基因型频率差异也极显著(P＜0.01) , 淮猪与杜洛克和约克夏这两个国外猪种基因型频率差异不显著(P＞0.05), 而与皮特兰和其他地方猪种的基因型频率均存在极显著差异(P＜0.01) 。通过测序在扩增片段中新发现了3种类型的碱基突变, 前2个分别导致了Thr和Glu向Ala和Arg的替换, 最后一个突变不引起氨基酸的变化, 且后两个突变位点为BB基因型所特有。     

Computational screening of disease associated mutations on NPC1 gene and its structural consequence in Niemann-Pick type-C1

Niemann-Pick disease type C1 （NPC1）, caused by mutations of NPC1 gene, is an inherited lysosomal lipid storage disorder. Loss of functional NPC1 causes the accumulation of free cholesterol （FC） in endocytic organelles that comprised the characteristics of late endosomes and/or lysosomes. In this study we analyzed the pathogenic effect of 103 nsSNPs reported in NPC1 using computational methods. Rl186C, S940L, R958Q and I1061T mutations were predicted as most deleterious and disease associated with NPC1 using SIFT, Polyphen 2.0, PANTHER, PhD-SNP, Pmut and MUTPred tools which were also endorsed with previous in vivo experimental studies. To understand the atomic arrangement in 3D space, the native and disease associated mutant （Rl186C, S940L, R958Q and I1061T） structures were modeled. Quantitative structural and flexibility analysis was conceded to observe the structural consequence of prioritized disease associated mutations （R1186C, S940L, R958Q and I1061T）. Accessible surface area （ASA）, free folding energy （FFE） and hydrogen bond （NH bond） showed more flexibility in 3D space in mutant structures. Based on the quantitative assessment and flexibility analysis of NPC1 variants, I1061T showed the most deleterious effect. Our analysis provides a clear clue to wet laboratory scientists to understand the structural and functional effect of NPCI gene upon mutation.     

The R1947X mutation of NF1 causing autosomal dominant neurofibromatosis type 1 in a Chinese family

Neurofibromatosis type 1 is a common autosomal dominant disorder with a high rate of penetrance. It is caused by the mutation of the tumor suppressor gene NF1, which encodes neurofibromin. The main function of neurofibromin is down-regulating the biological activity of the proto-oncoprotein Ras by acting as a Ras-specific GTPase activating protein. In this study, we identified a Chinese family affected with neurofibromatosis type 1. The known gene NF1 associated with NF1 was studied by linkage analysis and by direct sequencing of the entire coding region and exon-intron boundaries of the NF1 gene. The R1947X mutation of NF1 was identified, which was co-segregated with affected individuals in the Chinese family, but not present in unaffected family members. This is the first report, which states that the R1947X mutation of NF1 may be one of reasons for neurofibromatosis type 1 in Chinese population.     

不同栖息环境的两种啮齿动物Vkorc1基因多态性

维生素K环氧化物还原酶复合物亚基1基因(Vkorc1)的变异与啮齿动物对抗凝血灭鼠剂的抗药性密切相关。为掌握Vkorc1基因变异在野栖类和家栖类啮齿动物中的流行情况,从山西省13个县(市、区)的农田和14个县(市、区)的养殖场采样,检测长尾仓鼠(Cricetulus longicaudatus)和黄胸鼠(Rattus tanezumi) Vkorc1基因编码区的变异位点及携带不同变异位点的个体的分布情况。结果显示,长尾仓鼠在13个采样地均有捕获,整体占野栖类啮齿动物的23.29%;黄胸鼠分布于8个采样地,整体占家栖类啮齿动物的68.63%。在长尾仓鼠样本(n=105)中检测到6个沉默突变位点和5个错义突变位点,其中,沉默突变C438T (His146His)的变异率最高,为67.62%;共有17只长尾仓鼠样本存在错义突变位点。黄胸鼠样本(n=70)中存在6个沉默突变位点和1个错义突变位点,其中,最常见的沉默突变位点A321C (Ile107Ile)和T411C (Thr137Thr)的变异率均达到18.57%;8只黄胸鼠样本存在与其抗药性相关的A416G (Tyr139Cys)错义突变...     

Mutation load in melanoma is affected by MC1R genotype

Whole‐genome sequencing of matched germline and tumour pairs in a well‐characterized cohort of melanoma patients allowed investigation of associations between melanoma body site, age at melanoma onset and MC1R variant status with overall mutation burden and specific base pair changes observed in the corresponding melanoma. We observed statistically significant associations between mutation burden in melanoma and body site, age at onset and MC1R genotype, for both ultraviolet radiation (UVR) signature changes (C>T and CC>TT) and non‐UVR base pair substitutions, as well as with overall variant load.     

Novel transglutaminase 1 mutations in patients affected by lamellar ichthyosis

Lamellar Ichthyosis (LI) is a form of congenital ichthyosis that is caused by mutations in the TGM1 gene that encodes for the transglutaminase 1 (TG1) enzyme. Functional inactivation of TG1 could be due to mutations, deletion or insertions. In this study, we have screened 16 patients affected by LI and found six new mutations: two transition/transversion (R37G, V112A), two nonsense mutations and two putative splice site both leading to a premature stop codon. The mutations are localized in exons 2 (N-terminal domain), 5, 11 (central catalytic domain), and none is located in the two beta-barrel C-terminal domains. In conclusion, this study expands the current knowledge on TGM1 mutation spectrum, increasing the characterization of mutations would provide more accurate prenatal genetic counselling for parents at-risk individuals.     

Msx1 Gene Variant - its Association in Isolated Hypodontia: A Case Control Genetic study!!!

INTRODUCTION:

Non-syndromic tooth agenesis is a congenital anomaly with significant medical, psychological, and social ramifications. There is sufficient evidence to hypothesize that locus for this condition can be identified by candidate genes.

AIM OF THE STUDY:

The aim of this study was to test whether MSX1 671 T > C gene variant was involved in etiology of non-syndromic tooth agenesis in Raichur patients.

MATERIALS AND METHODS:

Blood samples were collected with informed consent from 50 subjects having non-syndromic tooth agenesis and 50 controls. Genomic deoxyribonucleic acid (DNA) was extracted from the blood samples, polymerase chain reaction (PCR) was performed, and restriction fragment length polymorphism (RFLP) was performed for digestion products that were evaluated.

RESULTS:

The results showed positive correlation between MSX1671 T > C gene variant and non-syndromic tooth agenesis in Raichur patients.

CONCLUSION:

MSX1 671 T > C gene variant may be a good screening marker for non-syndromic tooth agenesis in Raichur patients.     

中国4个少数民族中SDF1多态性研究

研究与HIV 1感染相关的基质细胞衍生因子 (SDF1)等位基因突变频率和多态性在中国 4个少数民族的分布特征。应用PCR/ RFLP等方法检测回族 (5 7例 )、鄂伦春族 (71例 )、蒙古族 (30例 )及锡伯族 (2 6例 )共 184个个体中SDF1 -3’A基因突变频率。结果得出中国 4个民族中SDF1- 3’A基因的基因频率分别为 :蒙古族为 38 3%,锡伯族为 2 3 .1%,回族为 2 0 .2 %,鄂伦春族为 10 .6 %。中国 4个少数民族中SDF1- 3’A等位基因频率存在较大的差异 (χ2 =37 .82 6 ,P<0.01) , 提示这 4 个民族的遗传结构存在着一定的差异。 本研究 为评估中国不同民族对 HIV-1 的易感性及艾滋病的流行病学研究提供了基本数据。     

乳腺癌易感基因BRCA1的研究进展

BRCA1基因是目前发现的外显率最高的乳腺癌易感基因之,编码一个相对分子质量为220000的多功能核蛋白,作用于一系列维持基因组稳定性的细胞通路,包括DNA损伤修复、细胞周期检验点激活、蛋白泛素化、染色质重组,以及转录调控和凋亡等。BRCA1丢失将导致显著的遗传不稳定性和生长停滞。着重介绍近年来BRCA1基础研究方面的进展,并讨论BRCA1与乳腺癌的临床关联性。     

一中国脑海绵状血管瘤家系中发现krit1基因新的缺失突变

脑海绵状血管瘤（CCM）是多定位于中枢神经系统的一种脑部血管异常,少数在皮肤和视网膜处有并发症。依据致病基因在染色体上的不同位置分为CCM1、CCM2和CCM33种类型。目前,CCM1、CCM2和CCM3的致病基因已经被克隆,分别为krit1、MGC4607和细胞程序性死亡10基因（PDCD10）。利用连锁分析发现内蒙古的一个家系属于CCM1,突变检测发现患者CCM1基因（krit1）第9内含子和第10外显子拼接位点处存在一“GTA”缺失,该突变导致终止密码子提前出现,产生截短蛋白。实验结果支持krit1为CCM1致病基因。     

中国遗传性胰腺炎患者胰蛋白酶原基因多位点杂合突变及其临床特征

用基因产物直接测序法对2个遗传性胰腺炎家系中胰腺炎患者(共有4例成员)的胰蛋白酶原基因(cationic trypsinogen,PRSS1)5个外显子进行测序,并分析其各自的临床特征.在4例胰腺炎患者中均出现了PRSS1基因杂合突变,但两家系PRSS1基因突变的位点不同,且临床表现差异较大,其中家系1出现6例糖尿病患者且发病年龄较家系2明显延迟,平均发病年龄为29岁,分析其PRSS1基因发现3号外显子336位碱基存在G→A杂合性突变,为中性突变,表达的氨基酸从赖氨酸(Lys)→赖氨酸(Lys),同时在同一外显子的361位碱基还存在另一个G→A杂合性突变,造成121位的丙氨酸(Ala)被苏氨酸(Thr)所取代,胰蛋白酶原的空间结构发生改变,其与抑制因子的结合位点消失,"保护失败"而产生有活性的胰蛋白酶,造成胰腺自身的消化.而家系2未发现糖尿病患者,其胰腺炎患者的血清肿瘤标志物不增高,先证者(Ⅲ8)在胰腺炎发病过程中表现为CD4 T/CD8 Tcell和乙肝表面抗体(anti-HBs)随病程进展逐渐降低,而Ⅲ7不表现出此现象,分析其PRSS1基因发现3号外显子361位碱基同样存在G→A(c.361G→A)突变,而且在415位还存在一个杂合性突变点T→A(c.415T→A),其中c.415T→A不存在于Ⅲ7.胰蛋白酶原基因存在多种形式的突变,而且与临床表型相关.     

先天性甲状腺功能减退症伴发育不全患儿FOXE1基因突变的初步研究

目的：研究先天性甲状腺功能减退症(CH)伴甲状腺发育不全患儿转录因子2( FOXE )的基因突变。方法：选取90 例CH伴甲 状腺发育不全患儿及90 例正常儿童作为对照,提取外周静脉血基因组DNA,采用PCR扩增与直接测序技术,对基因外 显子进行突变筛查。结果：分别在1 例先天性甲状腺功能减退症伴甲状腺发育不全患者外显子测序中发现一杂合错义变体c. A3401G (p.K1134R),在1 例患者中发现1 个已知的单核苷酸多态性(single nucleotide polymorphisms,SNP)位点(rs755282859, c. 483G>C),在正常对照组中未发现以上变化。结论：在先天性甲状腺功能减退症(CH) 伴甲状腺发育不全患儿中发现新的关于FOXE1 杂合错义变体。     

B para-Bombay phenotype in China caused by homozygous mutation for site 328 G > A of FUT1 gene: a case report

The aim of this paper is to accurately identify a case of B para-Bombay and to analyze the genetic mutation. ABO and Lewis blood groups were identified by standard serological methods, and trace antigens on RBCs were detected by adsorption-elution test, while blood group substances in the saliva were detected by agglutination inhibition test. The ABO gene exons 6-7, FUT1 gene exon 4 and FUT2 gene exon 2 were directly sequenced. Serological results showed that there were B antigens on RBCs without H antigens, anti-A and anti-HI antibodies in serum, and B and H blood group substances in the saliva. The Lewis phenotype was Le (a-b+). According to gene sequencing analysis, ABO, FUT1 and FUT2 genotypes were B101/O02, h^328G/Ah3^28G/A and Se^357C/TSe^357C/T, respectively. This rare phenotype can be mislabeled as "O" if any of the detailed investigations are not performed. Therefore, in order to ensure the safety of blood transfusion, genetic and serological tests are necessary for the correct identification of difficult blood groups.     

视网膜色素变性中GUCA1B、GNGT1和RGS9基因突变筛查

为寻找视网膜色素变性的致病基因,从120个家系收集视网膜色素变性先证者,制备基因组DNA。应用PCR―异源双链-SSCP法,分析GUCA1B基因4个外显子、GNGT1基因编码区和RGS9基因视网膜特异性转录区,寻找基因变异。序列分析确定突变。结果表明,31人的GUCA1B基因外显子1存在T/C多态。所有先证者中均未检测到GUCA1B、GNGT1和RGS9基因突变。认为本组病例未发现GUCA1B、GNGT1和RGS9基因的突变。 Abstract:To screen possible disease-causing mutations in the GUCA1B gene,GNGT1 gene,and the alternative-splicing region of RGS9 gene in 120 probands with retinitis pigmentosa,genomic DNA was collected from 120 probands with retinitis pigmentosa out of 120 families.The coding sequences of the GUCA1B and GNGT1 genes and the alternative splicing region of the RGS9 gene were analyzed by using PCR-heteroduplex-SSCP method.Mutation was confirmed by DNA sequencing.A T/C polymorphism was identified in exon 1 of the GUCA1B gene in 31 of the 120 probands.Heteroduplex-SSCP analysis of the GUCA1B and GNGT1 coding regions and RGS9 alternative splicing region showed no mutations in 120 patients with retinitis pigmentosa.We found no evidence that mutation in GUCA1B,GNGT1,or RGS9 gene is a cause of retinitis pigmentosa.     

肌萎缩侧索硬化患者SOD1基因突变检测及突变与临床表型的关系

应用PCR技术结合DNA直接测序方法对8例临床确诊为家族性肌萎缩侧索硬化(Familiar amyotrophic lateral sclerosis,FALS)家系的先证者进行铜锌超氧化物歧化酶基因(SOD1)的突变筛查,在3例先证者中检出2种SOD1基因突变,其中,2例携带了位于4号外显子的错义突变Cys111Tyr(c.332G>A),另1例携带了位于5号外显子的错义突变Gly147Asp(c.440G>A),这2种突变在中国ALS患者中属首次报道。该结果扩大了中国FALS患者的SOD1基因突变谱,对研究中国FALS患者SOD1基因突变特点和分布规律有一定帮助。分析携带这2个突变患者的临床特点,提示Cys111Tyr突变导致的临床表型相对温和,而Gly147Asp突变可导致病情进展较快。该结果有待在更多的病例中进行证实。     

在两个X连锁显性腓骨肌萎缩症家系中发现同一GJB1基因突变Glu208Lys

在两个X连锁显性腓骨肌萎缩症(Charcot-Marie-Tooth disease, CMT) 家系中进行了GJB1基因的突变分析。提取基因组DNA, PCR(polymerase chain reaction)反应扩增GJB1基因编码序列, 进行单链构象多态性(single strand conformational polymorphism, SSCP)分析, 对有差异SSCP带型的PCR产物进行测序, 结果在两家系中发现同一GJB1基因c.622G→A (Glu208Lys)突变。所发现的突变位点在国内尚未报道。