p53基因5/6外显子突变与广西肝癌高发区肝癌家族聚集性的相关性

为了研究p53基因5/6外显子突变与广西肝癌高发地区肝癌家族聚集性的关系。研究采用配对方法,选取肝癌高发家族、肝癌单发家族和无癌家族中未发生肝癌的家族成员各130例作为研究对象,同时选取上述高发地区肝癌患者30例作为肝癌组对照。应用PCR-SSCP技术检测研究对象外周血细胞DNA中p53基因5/6外显子的突变情况并进行基因测序。研究发现三组家族成员中p53基因5/6外显子的突变率为0%。肝癌组中p53基因5/6外显子的总突变率为10%(3/30)。肝癌组p53基因5/6外显子的总突变率与肝癌家族组间突变率比较,差异均具有统计学意义(p0.05)。综上,p53基因5/6外显子突变可能不是广西肝癌高发区肝癌家族聚集性的遗传易感因素,广西肝癌高发区肝癌家族成员中可能尚未发生p53基因5/6外显子突变或较为罕见,肝癌患者中出现的p53基因5/6外显子突变可能是在后天多因素的影响下发生,从而参与了肝癌的发生发展。     

酿酒酵母S期检查点通路上web2基因与rad53基因的位置关系

为探讨酿酒酵母(S.cerevisiae)S期检查点通路上,web2(wants E1A badly2,web2)基因与rad53基因的上下游位置及相互作用关系,利用羟基脲(hydroxyurea,HU)分别阻断web2突变株和野生株细胞的DNA合成.采用pHA- rad53质粒救助实验测定质粒源性Rad53蛋白是否能救助web2突变株对羟基脲的敏感性;Western印迹及免疫共沉淀反应检测Rad53蛋白表达及磷酸化.结果显示,pHA-rad53质粒可以救助web2突变株的存活;Western印迹检测到web2突变株内质粒源性Rad53蛋白表达增强而且至少Rad53部分蛋白为磷酸化蛋白.说明在HU作用下,过表达并磷酸化的质粒源性Rad53蛋白可以救助web2突变株的S期检查点功能缺陷,在酿酒酵母S期检查点通路上web2基因位于rad53基因上游,可能直接参与将检查点信号传递至Rad53蛋白.     

PTEN基因和P53基因在子宫内膜癌中的表达及意义

目的:探讨PTEN基因和P53基因在子宫内膜癌中的表达及临床意义,为子宫内膜癌的治疗提供参考依据。方法:用免疫组化法检测50例子宫内膜癌患者PTEN基因缺失和P53基因突变情况,并分析两者与子宫内膜癌不同病理变化的相关性。结果:PTEN缺失24例,缺失率48.00%,进一步研究显示PTEN缺失与细胞分化程度和肌层浸润情况密切相关(P0.05),P53突变32例,缺失率64.00%,并进一步研究显示P53突变与FIGO分期,细胞分化程度和肌层浸润情况密切相关(P0.05)。结论:PTEN基因缺失和P53基因突变与子宫内膜癌发生和发展密切相关,以PTEN基因和P53基因为靶点的生物治疗在进展期内膜癌中的治疗价值值得进一步深入研究。     

BRAF和TP53基因热点突变的构建

目的:构建BRAF和TP53基因多个位点的点突变质粒,为进一步研究其在肿瘤形成中的作用奠定基础。方法:以HEK-293T基因组DNA为模板构建含BRAF600、TP53175和TP53248位点的野生型质粒,利用MutanBESTTM定点突变方法获得含BRAFV600E、TP53R175C和TP53R248W等突变位点的突变型质粒,并进行DNA测序鉴定。结果:DNA测序结果显示构建的三个点突变与实验设计完全一致。结论:成功构建了BRAFV600E、TP53R175C和TP53R248W三个具有不同突变位点的突变型质粒,MutanBESTTM定点突变技术是一种简单、快速、高效的基因定点突变方法。     

应用免疫组织化学技术检测非小细胞性肺癌的P53蛋白

正常P53蛋白半衰期短,用普通免疫组织化学方法检测不出。而突变后的P53蛋白主要通过与病毒蛋白结合使其稳定性增强,延长其半衰期,从而细胞内P53蛋白增多,使用普通免疫组织化学方法即可检出。Iggo等通过对P53蛋白和p53基因的检测分析,发现p53基因在肿瘤组织中的高表达可以预示p53基因产生了点突变,从而可以采用较简便的方法来对     

p53：一个具有双面性的癌基因

根据经典的癌症遗传学，有两类癌症诱发的基因突变：一类是原癌基因（Oncogenes），其突变后增加了表达或功能；另一类是肿瘤抑制基因tumour suppressor genes），突变后导致其丧失表达或功能，这些都作为肿瘤的诱发事件。从1979年发现到1980年代后期，p53都被认作原癌基因。但是后来的研究又对该基因进行了重新分类，这是由于发现在肿瘤细胞中p53突变和基因缺失，     

幽门螺杆菌及其细胞毒素相关蛋白A与胃癌形成的关系及可能机制

目的通过检测慢性浅表性胃炎(CSG)、慢性萎缩性胃炎(CAG)、肠上皮化生(IM)、不典型增生(DYS)、胃癌(GC)组织幽门螺杆菌(Hp)和细胞毒素相关蛋白A(CagA)基因、P53、一氧化氮合成酶(iNOS)的表达,探讨Hp、CagA基因、P53、iN-OS与胃癌相关性及其参与胃癌形成的可能机制。方法应用快速尿素酶试验和组织切片革兰氏染色和血清HpCagA抗体检测Hp表达,用PCR检测HpCagA基因表达,用免疫组化SP法检测上述组织的突变P53蛋白、iNOS表达。结果 CSG、CAG、IM、DYS、GC组织中Hp检出率分别为46.7%、67.2%、70.0%、75.3%和53.8%,相应组织中HpCagA检出率分别为34.3%、59.0%、65.7%、69.1%和76.8%,GC组Hp感染率与DYS组相比差异显著(P<0.05),而CAG、IM、DYS组与CSG组Hp感染率相比差异显著(P<0.05)。IM、DYS、GC组CagA+株感染率则高于CSG组(P<0.01-P<0.05),GC组CagA+株感染率则高于CAG组(P<0.05)。从CSG到GC胃粘膜演变中,CagA基因阳性组中的突变P53、iNOS表达逐渐升高;除CSG外,CAG、IM、DYS、GC组CagA基因阳性组突变P53表达明显高于CagA基因阴性组突变P53表达(P<0.005-P<0.05);CSG、CAG、IM、DYS、GC组CagA基因阳性组iNOS表达均高于CagA基因阴性组iNOS表达(P<0.005-P<0.05)。结论 Hp特别是CagA基因与胃癌形成有关,Hp、CagA引起iNOS表达增高,P53基因突变,在形成胃癌中发挥作用,但P53基因突变在胃癌形成中属于较晚期事件。     

三阴乳腺癌P53突变热点及与预后的关系

目的:探讨三阴乳腺癌(TNBC)P53基因热点突变的情况及其与预后的关系。方法:选取2007年1月至2010年12月四川省人民医院收治的71例TNBC患者作为研究对象,采用免疫组化法检测71例TNBC患者手术石蜡标本的P53蛋白表达情况,采用ADx-ARMS方法检测P53基因突变热点情况,并分析两者与TNBC复发转移的关系。结果:71例患者总共有14例出现复发或转移,复发或转移发生率为19.7%。71例患者P53蛋白阳性表达率为69.0%,P53蛋白表达阳性患者的复发或转移率为18.4%,与P53蛋白表达阴性患者的复发或转移率22.7%比较,差异无统计学意义(P0.05)。总共有5例患者检出P53热点突变,P53热点突发生率为7.0%。P53热点突变全部都在P53蛋白阳性表达的患者中检出,而有P53热点突变的患者均没有出现复发或转移。结论:P53热点突变在TNBC患者中发生率不高,均出现在有P53蛋白阳性表达的患者中,而出现P53热点突变的患者预后较好。     

大肠癌中p53基因突变的研究

应用聚合酶链反应(PCR)──单链构型多态性(SSCP)结合银染法对14例大肠癌p53基因的第4、第5─6和第7外显子进行了点突变的研究,结果共检测出6例点突变,而且发现各外显子的突变频率存在差异。另外,利用购自ATCC的两个探针 (p53cDNA探针和pYNZ22探针)对大肠癌中p53基因的杂合性失去进行了研究,在14例大肠癌中共检出6例杂合性丢失。将点突变检测结果同杂合性丢失结果进行比较分析, 并着重探讨了大肠癌中p53基因失活导致肿瘤的作用方式。 Abstract:The exons 4-7 of p53 gene were examined in 14 colorectal Cancer patients by using PCR-SSCP-silver staining method.The results showed 6 cases of point mutation and the mutation frequencies of exons were different from each other.p53 cDNA and pYNZ22 VNTR were used as probes to examine LOH(Loss of heterozygosity)of 14 colorectal cancers.6 cases with LOH were found.The results of present research suggest that mutation and LOH of p53 gene are critical events in the progress and development of Cancer.There were different kinds of inactivation model of p53 gene in the process of development of cancer and transformation of cells.     

WEB2基因在酿酒酵母S期检查点通路上调控RNR3基因表达

WEB2基因参与酿酒酵母S期检查点调控机制,而RNR3基因位于该调控通路末端,DNA损伤或合成阻断时,S期检查点通路诱导RNR3过度表达。因此,通过确定WEB2在该检查点通路上是否参与调控RNR3基因的表达,将有助于进一步明确WEB2基因在检查点通路上的工作位点,了解WEB2基因如何发挥检查点调控功能。构建RNR3-LacZ基因融合质粒,用于检测酵母细胞内RNR3基因的诱导性。诱导性可以通过测定β-半乳糖苷酶的活性而得知。利用DNA损伤药物甲磺酸甲酯(MMS)及DNA合成阻断剂羟基脲(HU)处理酵母细胞,测定WEB2基因突变株和野生株细胞内RNR3基因的诱导性。结果,WEB2突变株细胞中诱导活性分别增加(8.27±0.38)倍和(9.55±0.24)倍,而野生株分别增加了(83.32±2.42)倍和(124.67±2.87)倍。反映RNR3基因在WEB2突变株中的诱导性低于野生株。同RAD53突变株相比,后者的RNR3基因的诱导性更低,仅为(2.37±0.18)倍和(2.91±0.13)倍。说明WEB2基因突变影响S期检查点通路的信号传递至RNR3基因,所以在酿酒酵母S期检查点通路上,WEB2工作在RNR3基因上游,参与调控RNR3的表达,但调控能力不如RAD53基因强。     

Recent advances in the study of Kaposi's sarcoma-associated herpesvirus replication and pathogenesis

It has now been over twenty years since a novel herpesviral genome was identified in Kaposi's sarcoma biopsies. Since then, the cumulative research effort by molecular biologists, virologists, clinicians, and epidemiologists alike has led to the extensive characterization of this tumor virus, Kaposi's sarcoma-associated herpesvirus(KSHV; also known as human herpesvirus 8(HHV-8)), and its associated diseases. Here we review the current knowledge of KSHV biology and pathogenesis, with a particular emphasis on new and exciting advances in the field of epigenetics. We also discuss the development and practicality of various cell culture and animal model systems to study KSHV replication and pathogenesis.     

The structure, reproduction and taxonomy of Vidalia and Osmundaria (Rhodophyta, Rhodomelaceae)

Comprises species occurring mostly in subtidal habitats in tropical, subtropical and warm-temperate areas of the world. An analysis of the type species, V. spiralis (Sonder) Lamouroux ex J. Agardh, a species from Australia, establishes basic characters for distinguishing species in the genus. These characters are (1) branching patterns of thalli, (2) flat blades that may be spiralled on their axis, (3) width of the blade, (4) primary or secondary derivation of sterile and fertile branchlets and (5) position of sterile and fertile branchlets on the thalli. Application of the latter two characters provides an important basic method for separation of species into three major groups. Osmundaria , a genus known only in southern Australia, was studied in relation to Vidalia , and its separation from the Vidalia assemblage is not accepted. Species of Vidalia therefore are transferred to the older genus name, Osmundaria. Two new species, Osmundaria papenfussii and Osmundaria oliveae are described from Natal. Confusion in the usage of the epithet, Vidalia fimbriala Brown ex Turner has been clarified, and Vidalia gregaria Falkenberg, described as an epiphyte on Osmundaria pro/ifera Lamouroux, is revealed to be young branches of the host, Osmundaria prolifera.     

New or rare chromosome counts in Artemisia L. (Asteraceae, Anthemideae) and related genera from Kazakhstan

Fifteen chromosome counts of six Artemisia taxa and one species of each of the genera Brachanthemum, Hippolytia, Kaschgaria, Lepidolopsis and Turaniphytum are reported from Kazakhstan. Three of them are new reports, two are not consistent with previous counts and the remainder are confirmations of very scarce (one to four) earlier records. All the populations studied have the same basic chromosome number, x = 9, with ploidy levels ranging from 2x to 6x. Some correlations between ploidy level, morphological characters and distribution are noted.     

肝癌中HBV和HCV基因和抗原的分布及意义

采用原位分子杂交方法检测HCV RNA及HBV X基因;采用免疫组织化学方法研究HCV核心抗原,非结构区C33c抗原及HBxAg在肝细胞肝癌中的定位及分布.结果表明(1)HCV RNA、HBV X基因在肝细胞肝癌组织检出率分别为40%(55/136)和82%(112/136).HCV RNA定位于癌细胞的胞浆内,阳性细胞呈散在、灶状及弥漫分布三种形式;HBV X基因在肝癌细胞中的分布呈胞浆型、核型及核浆型,阳性细胞也呈上述三种分布形式;(2)HCV C33c抗原、核心抗原在肝细胞肝癌中的阳性率为81%(133/164)及86%(141/164).C33c抗原定位于癌细胞及肝细胞的胞浆内;核心抗原既定位于癌细胞核中,又可定位于胞浆中.C33c抗原阳性细胞以灶状分布为主;而核心抗原阳性细     

Selection with two alleles and complete dominance

For a plant selection model with frequency-independent viabilities, fertilities and selfing rates, it is shown that apart from global fixation, for certain parameter combinations a protected polymorphism and facultative fixation (either allele may become fixed according to initial frequencies) may both occur. Facultative fixation requires different selling rates for the dominant and recessive type. Protection of the polymorphism requires resource allocation for male and female function. In this connection the problem of purely genetically caused population extinction is discussed.
For general frequency dependence and regular segregation, the chances for establishment of a completely recessive gene are compared to those of a completely dominant gene. It is proven that the process of establishment of the recessive gene, despite a fitness advantage, may be considerably endangered by drift effects if random mating prevails. The recessive gene may reach the same effectivity in establishment as a dominant gene, only if the recessive homozygote mates exclusively with its own type during the period of establishment.