Contrasting mutation rates in mitochondrial and nuclear genes of yeasts versus mammals

Summary Base substitutions have been compared in two mitochondrial and two nuclear genes from three yeasts and three mammals. In yeasts, the two mitochondrial genes, cytochrome oxidase subunit 2 (COX2) and apocytochrome b (CYB), have fewer changes on a percentage basis than the nuclear-encoded cytochrome c (CYC) gene. By contrast, in mammals, the same mitochondrial genes have more mutations than CYC on a percentage basis. Sequence comparisons of the nuclear small-subunit ribosomal RNA (nSSU) gene shows that there are more substitutions per unit length in the three yeasts than in the three mammals. This result suggests that although the yeasts are more distantly related than the mammals, their mitochondrial genes have accumulated fewer changes.     

热休克反应对大鼠油酸肺保护作用的机制研究

未研究发现，经热休克处理的大鼠注油酸后，肺组织损伤明显减轻，Ｗｅｓｔｅｒｎ印迹分析显示热休克使大鼠肺组织中ＨＳＰ７０含量明显增多；Ｎｏｒｔｈｅｒｎ印迹分析证实此乃由于ＨＳＰ７０ｍＲＮＡ转录增加所致。说明热休克处理使肺组织ＨＳＰ７０基因表达增强；提示热休克反应对大鼠油酸肺的保护作用与肺组织细胞中ＨＳＰ７０基因表达增强及与ＨＳＰ７０增多有关。     

BRCA2与LIM结构域蛋白FHL2的相互作用

目的：应用酵母双杂交方法筛选BRCA2相互作用蛋白编码基因，验证其相互作用并研究其功能联系。方法：以BRCA2基因3′端片段构建酵母双杂交质粒，筛选正常人乳腺上皮细胞cDNA库，获得编码相互作用蛋白的基因，采用免疫共沉淀、哺乳细胞双杂交和荧光酶测定等方法进一步验证蛋白间相互作用和功能联系．结果：采用酵母双杂交系统筛选，获得了多个编码BRCA2相互作用蛋白的基因，其中包括已知的FHL2蛋白；免疫共沉淀和哺乳动物细胞双杂交试验显示BRCA2和FHL2在体内特异性结合，并证实FHL2在体内形成同源二聚体；转录活性分析发现BRCA2与FHL2有协同转录激活作用。结论：发现BRCA2与FHL2蛋白间相互作用和功能联系，为BRCA2功能研究提供了新的方向。     

人白细胞介素12双亚基共表达真核载体的构建

目的 :为满足基因治疗的需要构建人白细胞介素 12 (hIL 12 )双亚基共表达质粒。方法 :先从人胚肾组织的逆转录产物中用PCR方法扩增出它的两个亚基P4 0 和P3 5的cDNA全长 ,分别克隆入真核表达载体pcDNA3.1(+/ )中构建单亚基质粒———P(+) /P4 0 和P( ) /P3 5,然后再将二者串联克隆入真核表达载体 pcDNA3.1(+)中得到P(+) /IL 12质粒。脂质体转染HepG2后 2 4,48hELISA检测细胞培养上清内hIL 12蛋白质表达。结果 :P(+) /IL 12质粒经酶切和测序证明两亚基连接方向正确 ,序列无突变 ;ELISA检测细胞上清结果证实可表达hIL 12蛋白质。结论 :成功构建P4 0 和P3 5双亚基真核共表达质粒———P(+) /IL 12 ,为模拟hIL 12生理表达方式 ,简化hIL 12基因治疗操作奠定了基础。     

The ordered transmission disequilibrium test: detection of modifier genes

We consider the problem of detection of modifier genes that lead to variations in a disease‐related continuous variable (DRCV), such as the age of onset or a measure of disease severity, in a strategy of candidate genes. We propose a novel method, the ordered transmission disequilibrium test (OTDT), to test for a relation between the clinical heterogeneity expressed by a DRCV and marker genotypes of a candidate gene. The OTDT applies to trio families with one patients and his parents, all three genotyped at a bi‐allelic marker M. The OTDT aims to find a critical value of the DRCV which separates the sample of families in two subsamples in which the transmission rates are significantly different. We investigate the power of the method by simulations under various genetic models and covariate distributions and compare it with a linear regression analysis. Genet. Epidemiol. 2008. ©2008 Wiley‐Liss, Inc.     

p21-ras、p53和VEGF在甲状腺乳头状癌中的表达及意义

目的　研究原癌基因Ras、抑癌基因p5 3及血管内皮生长因子 (VEGF)在甲状腺乳头状癌中的表达及相关性。方法　应用免疫组织化学S P法对 4 0例甲状腺乳头状癌中p2 1 ras、p5 3及VEGF的表达进行研究。结果　甲状腺乳头状癌中存在p2 1 ras、p5 3及VEGF的过度表达 ;VEGF的表达与p2 1 ras、p5 3的表达显著相关 (P <0 .0 5 ) ;VEGF的表达与甲状腺乳头状癌淋巴结转移显著相关 (P <0 .0 5 )。结论　p2 1 ras、p5 3、VEGF在甲状腺乳头状癌的发生发展过程中起重要作用 ;VEGF的表达与p2 1 ras、p5 3表达显著相关 ,可能受其调控。     

纤溶酶原激活剂抑制物-1及其基因多态性与急性心肌梗死的相关性研究

目的：研究纤溶酶原激活剂抑制物－1（PAI－1）活性及其等位基因多态性与急性心肌梗死（AMI）之间的关系，从基因水平揭示AMI发病的危险因素。方法：AMI组55例、对照组48例健康者分别应用特异性寡核苷酸点膜杂交技术，进行PAI－1启动子区4G／5G多态性分析，用发色底物法测定血浆PAI－1活性。结果：AMI组和对照组中4G／4G基因型的血浆PAI－1活性水平最高，与4G／5G基因型、5G／5G基因型比较有显著性差异（P＜0．01）。AMI组中4G／4G纯合子基因型频率明显高于对照组（P＜0．05）。结论：血浆PAI－1活性增高是AMI发病的危险因素之一，4G／4G纯合子基因型是AMI发病的危险基因型。     

Absence of structural alterations of the multidrug resistance genes in transitional cell carcinoma

Summary Tumor DNA from 27 patients with treated or untreated transitional cell carcinomas of the urinary tract was screened for genomic alterations of the multidrug resistance genes in order to determine whether structural changes of these genes are important in primary urothelial tumors. None of the tumors showed evidence of amplification or rearrangements of either mdr1 or mdr2. The lack of amplification or rearrangements observed in these tumors suggests that structural alterations of the mdr1 and mdr2 genes are not important mediators of drug resistance in TCC.Supported in part by grant CA-34775 from the National Institutes of Health and by a grant from the Heckscher Foundation for ChildrenDr. Klein is a fellow of the American Cancer Society     

115 BRCA1基因与乳腺癌研究进展

乳腺癌易感基因BRCA1作为抑癌基因,其编码产物在细胞周期调控、DNA损伤修复以及肿瘤细胞的凋亡中扮演着重要角色.大量研究证明,BRCA1基因结构、功能异常与乳腺癌的发生发展有十分密切的联系.本文拟就BRCA1与乳腺癌相关研究的最新进展作一综述.