羟基脲促进HEL细胞分化机制的研究

以往研究表明, 用羟基脲诱导人红白血病细胞（ＨＥＬｃｅｌｌ）后, 能促进成年型β珠蛋白基因表达, 使ＨＥＬ细胞趋向终末分化。本文试图进一步揭示羟基脲诱导ＨＥＬ细胞分化的分子机制。ＧＭＳＡ 与Ｗｅｓｔｅｒｎ 印迹分析结果显示, 随着羟基脲诱导ＨＥＬ 细胞时间延长, 细胞核内的ＧＡＴＡ１ 转录因子的含量增加, 它与β珠蛋白基因５＇旁侧ＤＮＡ 序列内一个正调控序列（ＰＣＲ：－ ２２３～－ １９４ ｂｐ） 以及人工合成的ＧＡＴＡＤＮＡ 序列结合能力增加; 与此相反,细胞核内的ＧＡＴＡ２ 转录因子的含量下降, 它与ＧＡＴＡＤＮＡ 序列结合能力也下降。此外, 还检测到在羟基脲诱导ＨＥＬ细胞后, 核内与ＹＹ１ 类似的一个转录因子含量也迅速下降。实验结果表明ＧＡＴＡ２ 可能在红系细胞早期分化中起重要作用, 而ＧＡＴＡ１ 则在红系细胞终末分化过程中起调控作用。推测类似ＹＹ１ 的一个转录因子可能具有抑制ＨＥＬ细胞趋向终末分化的功能     

玉米反式因子基因分离初报

发育是一个严格有序的选择性基因表达过程。在这一过程中,序列特异的反式因子（ｔｒａｎｓａｃｔｉｎｇｆａｃｔｏｒｓ）通过与基因调控序列中顺式调控元件（ｃｉｓａｃｔｉｎｇｅｌｅｍｅｎｔｓ）的互作启动基因转录,因此,它们又被称为转录因子［１］。基于这类因...     

PKC对人mdr1基因转录调控的研究

研究了ＰＫＣα、β１和β２亚型对多药耐药基因ｍｄｒ１转录的调控作用．以ｍｄｒ１基因上游调控序列驱动的虫荧光素酶报告基因表达载体和ＰＫＣ基因表达载体共同转染ＣＯＳ７细胞后,测定虫荧光素酶报告基因表达水平．实验结果表明,ＰＫＣα、β１及β２对ｍｄｒ１基因的转录有下调作用,ＰＭＡ可进一步加强这一作用;在此转染体系中,ＰＫＣ抑制剂ｓｔａｕｒｏｓｐｏｒｉｎｅ也可抑制ｍｄｒ１基因的转录,但在只转染ｍｄｒｌｕｃ的细胞中,ｓｔａｕｒｏｓｐｏｒｉｎｅ对ｍｄｒ１的转录则没有影响,提示ｓｔａｕｒｏｓｐｏｒｉｎｅ仅在ＰＫＣ过量表达的细胞中抑制ｍｄｒ１基因的转录．     

家鸡血清酯酶遗传多态现象的发育遗传学初步研究

采用垂直平板聚丙烯酰胺凝胶电泳方法随机抽样了后备,初产和产蛋３个阶段的优黄２０００肉种鸡血清酯酶的遗传多态性,结果表明：血清酯酶Ｅｓ－１和Ｅｓ－２均存在遗传多态现象,Ｅｓ－１区检出２－３条多态性酶带,Ｅｓ－２区仅有１条带,表型为带的有或无。     

人鼻咽癌细胞基因组中瘤基因Ha－ras－1的Dnase Ⅰ超敏感位点的初步研究

ＤＮａｓｅⅠ超敏感位点的研究能够发现潜在的调控基因转录活化的位点,比较正常人外周血有核细胞,淋巴瘤细胞株Ｐ３ＨＲ１和人鼻咽癌低分化磷癌细胞株ＨＯｎＥ１和ＨＮＥ２中Ｈａ－ｒａｓ－１瘤基因的ＤＮａｓｅⅠ超敏感位点发现,只有ＨＯＮＥ１和ＨＮＥ２细胞基因组中存在一个ＤＮａｓｅⅠ超敏感位点,位于第一个外显子上游０．３７ｋｂ处,上述结果提示正常白细胞和Ｐ３ＨＲ１细胞中Ｈａ－ｒａｓ－１基因处于失活状态,而在鼻咽癌细胞基因组中则处于活化状态,它的活化可能与０．３７ｋｂ处的ＤＮＡ序列有密切的关系。     

EF—Tumt和EF—Tsmt在不同发育阶段小鼠各组织中的表达分析

线粒体蛋白质翻译延长因子Ｔｕ和Ｔｓ（ｍｉｔｏｃｈｏｎｄｒｉａｌｅｌｏｎｇａｔｉｏｎｆａｃｔｏｒＴｕａｎｄＴｓ,ＥＦＴｕｍｔａｎｄＥＦＴｓｍｔ）是由核基因编码的两个蛋白质,它们的功能和调控对细胞的生长发育有重要意义。采用ＥＦＴｕｍｔ和ＥＦＴｓｍｔ重组蛋白分别制备了抗ＥＦＴｕｍｔ和抗ＥＦＴｓｍｔ特异抗体并以此检测了它们在小鼠不同发育时期心肌、骨骼肌、肝、脑、脾等组织中的表达。蛋白质印迹结果表明ＥＦＴｕｍｔ和ＥＦＴｓｍｔ在各组织中的表达水平不同、有明显的组织差异性,并都受发育的调节。ＥＦＴｕｍｔ在同一发育时期各组织中的表达及随发育的变化趋势与ＥＦＴｓｍｔ基本一致。结果提示ＥＦＴｕｍｔ和ＥＦＴｓｍｔ的表达水平与组织细胞能量代谢水平密切相关,它们不仅在体内以复合体形式发挥作用,其基因表达可能受同一机制的调控。     

水稻转座子TouristOs6 从sbe1 基因启动区切离的证明

为研究ｓｂｅ１ 基因的表达调控机理,籼稻ＩＲ３６ 品种的ｓｂｅ１ 基因被克隆。经测序后与已报告的ｓｂｅ１ 基因顺序相比,ＩＲ３６ 水稻品种ｓｂｅ１ 基因５’上游区顺序中除了有分散的３２ 个碱基差异外,值得注意的是缺少一段３３５ ｂｐ 长的ＴｏｕｒｉｓｔＯｓ６ 序列,并在缺失的位置上留下转座子切离后的特征性足印顺序,这表明ＩＲ３６ 品种的ＴｏｕｒｉｓｔＯｓ６ 已从ｓｂｅ１ 基因中切离。因而为ＴｏｕｒｉｓｔＯｓ６ 是可移动的转座子提供了一个有力的证据     

两种淡水鱼类的Sox基因

ＴＨＥＳＯＸＧＥＮＥＳＩＮＴＷＯＳＰＥＣＩＥＳＯＦＦＲＥＳＨＷＡＴＥＲＦＩＳＨＥＳ两种淡水鱼类的Ｓｏｘ基因ＫｅｙｗｏｒｄｓＳｅｘ,Ｉｎｔｒｏｎ,Ｆｒｅｓｈｗａｔｅｒｆｉｓｈ关键词性别内含子淡水鱼类ＴｈｅＳｒｙｉｓｔｈｅｓｅｘｄｅｔｅｒｍｉｎｉ...     

降血脂药物（DEHP）对酰基CoA氧化酶基因反式作用因子的影响

从对照和用ＤＥＨＰ处理的大鼠肝脏提取核蛋白,以含酰基ＣｏＡ氧化酶（ＡＯＸ）基因表达调控部位的ＤＮＡ片段和该基因的不同蛋白结合位点的ＤＮＡ片段作为核蛋白结合反应的探针,通过凝胶电泳迁移率改变实验和Ｓｏｕｔｈｗｅｓｔｅｒｎ印迹分析检查了ＤＥＨＰ对ＡＯＸ基因反式作用因子的影响。结果表明,降血脂药物ＤＥＨＰ可显著增加ＡＯＸ基因反式作用因子的含量和（或）与基因的结合活性,在转录水平上促进基因的表达。     

巨大芽孢杆菌α-淀粉酶基因核苷酸序列分析

巨大芽孢杆菌（Ｂａｃｉｌｕｓｍｅｇａｔｅｒｉｕｍ）ＡＳ１．１２７的淀粉酶基因的全碱基序列已被测定。结构基因由１９８２ｂｐ的单一开读框架组成。由ＤＮＡ序列推测出的前体酶蛋白由６５９个氨基酸组成,Ｎ端３３个氨基酸为信号肽。成熟酶分子由６２６个氨基酸组成,分子量为６８６７６ｋＤ。该淀粉酶属糖化型α淀粉酶。并与枯草杆菌（Ｂ．ｓｕｂｔｉｌｉｓ）１６８产生的糖化型α淀粉酶之间有８３３％的同源性。分析发现两种菌产生的酶分子的Ｎ端３／４的同源性为９０４％,而Ｃ端１／４的同源性只有７０％。序列排比结果说明在淀粉酶基因的趋异进化过程中,基因突变和遗传重组都曾起过作用。     

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.