FMRP蛋白6种异构体与FXR1蛋白间的相互作用

脆性Ｘ综合征是最常见的遗传性智力低下疾病,其致病基因ＦＭＲ１存在复杂的选择剪接．ＦＭＲ１基因的功能及其选择剪接的生物学意义尚未阐明．ＦＭＲ１蛋白（ＦＭＲＰ）与脆性Ｘ相关蛋白１（ＦＸＲ１）可形成异源二聚体．采用酵母双杂交体系研究了由ＦＭＲ１第１２、１４、１５外显子不同选择剪接方式产生的６种ＦＭＲＰ异构体与ＦＸＲ１蛋白的相互作用,以期从蛋白质相互作用的角度探讨ＦＭＲ１基因选择剪接表达的生物学意义．结果表明各种异构体与ＦＸＲ１相互作用的强度随异构体蛋白肽链长度的增长而减弱．外显子１２、１４、１５的选择剪接虽然不能开关式控制ＦＭＲＰ与ＦＸＲ１的相互作用,但其Ｃ端亲水区在一定程度上影响相互作用的强弱．提示选择剪接对ＦＭＲＰ与ＦＸＲ１异源二聚体的稳定性产生影响．     

FMR1基因功能研究的新进展

ＦＭＲ１基因突变引起表达缺乏,导致最常见的遗传性智力低下疾病－脆性Ｘ综合征。ＦＭＲ１基因编码的蛋白与翻译过程的调控。     

分子遗传学研究的新焦点：动态突变与脆性X综合征

近年来,对脆性位点分子生生物学的研究已取得突破性进展,脆性Ｘ综合征智力低候选基因ＦＭＲ－１已被克隆,其５＇端外显子是由一段不稳定的微随体序列ｎ组成,该ｎ重复序列拷贝数的遗传是不稳定的,其扩增长度的变化与脆性与点的表达,ＣｐＧ岛的甲基化,ＦＭＲ－１基因的功能,临床表型具有相关性,分子遗传学上把 这种独特的遗传形式称为“动态突变”。这一发现,为脆性Ｘ综合征及其它与动态突变有关的遗传病的研究提供了重要的     

脆性X蛋白的RNA伙伴

脆性Ｘ综合征是一种最常见的智力迟缓遗传病 .患者的Ｘ染色体上有一个单个的缺陷基因 ,尽管该缺陷基因已在十多年前鉴定出来 ,但仍不知其的发病原因 .导致该综合征的主要基因编码一个蛋白质 ,称为ＦＭＲＰ即脆性Ｘ蛋白质 ,其与ｍＲＮＡ链相结合 .神经科学家已提出理论认为当ＦＭＲＰ不能在细胞内部 ,特别是在脑细胞内部 ,适当地运送ｍＲＮＡ时 ,或不能正确调节ｍＲＮＡ制造蛋白质时 ,便会产生脆性Ｘ综合征。研究者将ＦＭＲＰ暴露于参与形成ｍＲＮＡ的多串亚基中发现ＦＭＲＰ与ｍＲＮＡ片段是紧密结合的。这种ｍＲＮＡ片段形成奇特的立方体结…     

大鼠FMR1同源基因cDNA的克隆、测序与选择剪接的初步分析

应用ＲＴ－ＰＣＲ方法,从新生大鼠脑组织总ＲＮＡ扩增大鼠ＦＭＲ１同源基因的ｃＤＮＡ片段,克降至ｐＵＣ１８质粒中进行序列分析．获得从终止密码子起共１６８１ｂｐ的编码序列,尚缺少约２００ｂｐ的５′序列．所克隆的这部分大鼠ＦＭＲ１ｃＤＮＡ,不含有对应于人ＦＭＲ１基因的外显子１２及外显子１７第一和第三剪接受点之间的序列,提示大鼠ＦＭＲ１基因也有选择剪接表达．同源性分析显示,大鼠ＦＭＲ１与小鼠ＦＭＲ１基因的同源性为９７．７％,与人ＦＭＲ１基因的同源性为９４．９％;与小鼠ＦＭＲＰ（ＦＭＲ１蛋白）的氨基酸序列同源性为９８．４％,与人ＦＭＲＰ的氨基酸序列同源性为９７．９％．以大鼠ＦＭＲ１ｃＤＮＡ片段为探针检测到大鼠不同组织中ＦＭＲ１基因的选择剪接表达．上述结果为以大鼠为动物模型深入研究ＦＭＲ１基因功能奠定了基础．     

显微注射法制备转基因小鼠模型的研究

将外源基因ＭＴ０ＬＭＰ,ｐＺｉｐＮｅｏＳＶ（Ｘ１）－ＬＭＰ及ＨＬＡ－ＤＲα分别注入昆明小鼠受精卵雄原核中,结果得到有这三种外源基因整合的三个转基因小鼠系,导入基因的整合率分别为８％,８０％骸６６．７％,它们的子一代及子二代（Ｆ２）基因中也均有外源基因整合,并且导入ｐＺｉｐ－ＮｅｏＳＶ９Ｘ１）－ＬＭＰ基因后经反转录聚合酶链反应,检测ｍＲＮＡ发现有该基因的表达,说明本法制备转基因小鼠是可行的。应用荧光     

动态突变与人类健康

动态突变与人类健康梁文兰（山东淄博市第二卫生学校２５５０１５）脆性Ｘ综合征［ｆｒａ（Ｘ）］,是一种常见的遗传性智力低下疾病。在遗传性智力障碍疾病中,其发病率仅次于先天愚型。占智力低下人群的０·５％～１０％,在Ｘ连锁智力低下中占４０％。其特征为不同程度...     

应用肌肉介导基因转移制备5,10亚甲基四氢叶酸还原酶(MTHFR)抗体

５,１０亚甲基四氢叶酸还原酶（ＭＴＨＦＲ）是叶酸代谢的关键酶．为了试验肌肉介导外源基因人ＭＴＨＦＲ（ｈＭＴＨＦＲ）制备抗体和建立ＭＴＨＦＲ免疫检测的可能性,构建了ＭＴＨＦＲ基因真核表达载体（ｐｃＤＮＡ３／ＭＴＨＦＲ）;通过基因缝线法将携带ｐｃＤＮＡ３／ＭＴＨＦＲ的质粒,缝合于预先注射再生剂（丁哌卡因）的肌肉内．２个月后分离血清,所得抗体应用Ｗｅｓｔｅｒｎｂｌｏｔ,ＥＬＩＳＡ和胎肝免疫组织化学染色进行免疫鉴定．胎肝免疫组织化学显示,在肝小梁细胞浆中具有大量ＭＴＨＦＲ阳性反应颗粒;Ｗｅｓｔｅｒｎｂｌｏｔ有ＭＴＨＦＲ抗体与其抗原特异的褐色条带,分子量约为３７ｋＤ;ＥＬＩＳＡ分析表明,３种不同浓度的抗体与不同剂量的抗原反应具有剂效关系,最适抗体滴度（ＥＤ５０）为１∶４００。以上结果说明肌肉介导外源基因是获得抗体的一种简单、快捷的方法．该抗体可用于ＭＴＨＦＲ的免疫检测和有关的叶酸代谢研究工作．     

西藏密花树属(紫金牛科)一新变种

西藏密花树属（紫金牛科）一新变种郑维列（西藏高原生态研究所，林芝８６００００）姚淦（中科院江苏植物研究所，南京２１００１４）ＡＮＥＷＶＡＲＩＥＴＹＯＦＲＡＰＡＮＥＡ（ＭＹＲＳＩＮＡＣＥＡＥ）ＦＲＯＭＸＩＺＡＮＧ（ＴＩＢＥＴ）ＺｈｅｎｇＷｅｉｌｉｅ１...     

江西蕨类植物新记录

江西蕨类植物新记录陈少风１谢庆红２程景福１（１．南昌大学生物科学工程系,南昌３３００４７）（２．江西九连山自然保护区管理处,江西３４１７０１）关键词蕨类植物;分布新记录;江西省;中国ＮＥＷＲＥＣＯＲＤＳＯＦＦＥＲＮＳＦＲＯＭＪＩＡＮＧＸＩ,ＣＨＩＮＡ...     

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.