分子生物學(xué)名詞解釋

1、.Isoaccepting tRNA：同工受體tRNA，能解讀同工密碼子的不同tRNA。inducer;（誘導(dǎo)物）凡能誘導(dǎo)操縱子開啟的效應(yīng)物稱為誘導(dǎo)物。Insulater（絕緣子）： 真核生物基因組的調(diào)控元件之一，亦為一種邊界元件。Promoter（啟動(dòng)子）：指DNA分子上被RNApol調(diào)節(jié)因子等識別并結(jié)合形成轉(zhuǎn)錄起始復(fù)合體的區(qū)域，是控制轉(zhuǎn)錄起始的序列。Gene（基因）：書 Enhancer (增強(qiáng)子)：是一個(gè)順式作用序列，能夠提高一些真核生物啟動(dòng)子的利用，并能夠在啟動(dòng)子任何方向以及任何位置(上游或者下游)作用。Gene /ciston (基因/順反子)：指能產(chǎn)生一條多肽鏈的DNA片段。包括編

2、碼區(qū)和其上下游區(qū)域(引導(dǎo)區(qū)和尾)，以及在編碼片段間(外顯子)的割裂序列(內(nèi)含子)。Gene family (基因家族)：一系列外顯子相關(guān)聯(lián)的基因，其成員是由一個(gè)祖先基因復(fù)制或趨異產(chǎn)生Induction (誘導(dǎo))：指細(xì)菌或者酵母只有當(dāng)?shù)孜锎嬖跁r(shí)才會合成某種酶的能力。當(dāng)用在基因表達(dá)中，指誘導(dǎo)物與調(diào)控蛋白結(jié)合造成的轉(zhuǎn)錄轉(zhuǎn)換。Initiation factors (起始因子，原核中IF，真核中eIF)：在蛋白質(zhì)合成起始階段特異性作用于核糖體小亞基的蛋白質(zhì)。Intron(內(nèi)含子)：一段DNA片段，它轉(zhuǎn)錄但通過將其兩端的序列(外顯子)剪接在一起而被移出轉(zhuǎn)錄本。Isoaccepting tRNAs (同工t

3、RNA)：攜帶相同的氨基酸的tRNA。Molecular chaperone (分子伴侶)：協(xié)助一些蛋白質(zhì)裝配或者恰當(dāng)折疊所需的蛋白質(zhì)，但這種蛋白質(zhì)并不是靶復(fù)合物的成分。Operator(操縱基因)：DNA 上的一個(gè)位點(diǎn)，阻遏蛋白能與之結(jié)合抑制相鄰啟動(dòng)子從而抑制轉(zhuǎn)錄。Primosome (引發(fā)體)：指在非連續(xù)DNA復(fù)制中，每個(gè)崗崎片段合成引發(fā)反應(yīng)中涉及的蛋白質(zhì)復(fù)合體。引發(fā)體能沿著DNA 移動(dòng)，參與連續(xù)的引發(fā)反應(yīng)。Promoter (啟動(dòng)子)：結(jié)合RNA 聚合酶并起始轉(zhuǎn)錄的DNA 區(qū)域-10 sequence (-10區(qū))：位于細(xì)菌基因起始位點(diǎn)上游10bp的一段保守序列TATAATG。在RNA聚

4、合酶誘導(dǎo)DNA 溶解起始時(shí)起作用。-35 sequence (-35區(qū))：細(xì)菌基因起始位點(diǎn)上游35bp處的保守序列，在RNA聚合酶起始識別中作用。Pseudogenes (假基因)：由原始活性基因突變引起的基因組中穩(wěn)定但不活潑的成分。Pseudogenes are segments of DNA that are related to real genes. Pseudogenes have lost at least some functionality, relative to the complete gene, in cellular gene expression or protei

5、n-coding ability.snRNPs：核小核糖體蛋白質(zhì)(snRNA 與蛋白質(zhì)結(jié)合)顆粒。negative regulation (負(fù)調(diào)節(jié)):當(dāng)細(xì)胞中存在的調(diào)節(jié)蛋白處于激活狀態(tài)時(shí),會使目的基因的表達(dá) 活性受到抑制,我們稱這種抑制基因表達(dá)活性的調(diào)節(jié)類型為負(fù)調(diào)節(jié)。順式作用元件(cis-acting element)存在于基因旁側(cè)序列中能影響基因表達(dá)的序列。順式作用元件包括啟動(dòng)子、增強(qiáng)子、調(diào)控序列和可誘導(dǎo)元件等，它們的作用是參與基因表達(dá)的調(diào)控。順式作用元件本身不編碼任何蛋白質(zhì)，僅僅提供一個(gè)作用位點(diǎn)，要與反式作用因子相互作用而起作用。Cis-Acting Element Download PD

6、F (6,857 KB)The Cis-acting element must be located in the same DNA strand as its target to act upon it during transcription. Genes that are conserved across species will also display conservation at the level of their transcriptional regulation and this will be reflected in the organization of cis-e

7、lements mediating this regulation. Using a computational approach, clusters of transcription factor binding sites that are absolutely conserved in order and in spacing across human, rat, and mouse genomes were identified.mutation hot spot(突變熱點(diǎn)):突變機(jī)率較高的堿基序列。trans-acting element反式作用因子：是指能直接或間接地識別或結(jié)合在各

8、類順式作用元件核心序列上參與調(diào)控靶基因轉(zhuǎn)錄效率的蛋白質(zhì)。多為轉(zhuǎn)錄因子。大多數(shù)真核轉(zhuǎn)錄調(diào)節(jié)因子由某一基因表達(dá)后，可通過另一基因的特異的順式作用元件相互作用，從而激活另一基因的轉(zhuǎn)錄。這種調(diào)節(jié)蛋白稱反式作用因子。轉(zhuǎn)錄因子: 真核基因的轉(zhuǎn)錄調(diào)節(jié)蛋白又稱轉(zhuǎn)錄調(diào)節(jié)因子或轉(zhuǎn)錄因子。Transcription factorIn molecular biology, a transcription factor (or sequence-specific DNA-binding factor) is a protein that controls the rate of transcription of gen

9、etic information from DNA to messenger RNA, by binding to a specific DNA sequence.12 In turn, this helps to regulate the expression of genes near that sequence. This is essential in embryogenesis.Transcription factors work alone or with other proteins in a complex, by promoting (as an activator), or

10、 blocking (as a repressor) the recruitment of RNA polymerase (the enzyme that performs the transcription of genetic information from DNA to RNA) to specific genes.345A defining feature of transcription factors is that they contain at least one DNA-binding domain (DBD), which attaches to a specific s

11、equence of DNA adjacent to the genes that they regulate.67 Transcription factors are usually classified into different families based on their DBDs.89 Other proteins such as coactivators, chromatin remodelers, histone acetyltransferases, histone deacetylases, kinases, and methylases, while also esse

12、ntial to gene regulation, lack DNA-binding domains, and, therefore, are not transcription factors.10終止密碼子：在mPNA翻譯過程中，起蛋白質(zhì)合成終止信號作用的密碼子，即UAA， UAG和UGAmulti gene family（多基因家族）是指由某一祖先基因經(jīng)過重復(fù)和變異所產(chǎn)生的一組基因。A methyltransferase is a type of transferase enzyme that transfers a methyl group from a donor to an acc

13、eptor.Methylation often occurs on nucleic bases in DNA or amino acids in protein structures. Methytransferases use a reactive methyl group bound to sulfur in S-adenosyl methionine (SAM) as the methyl donor.DNA methylation is often utilized to silence and regulate genes without changing the original

14、DNA sequence, an example of epigenetic modification. This methylation occurs on cytosine residues. DNA methylation may be necessary for normal growth from embryonic stages in mammals. When mutant embryonic stem cells lacking the murine DNA methyltransferase gene were introduced to a germline of mice

15、, they caused a recessive lethal phenotype.1 Methylation may also be linked to cancer development, as methylation of tumor suppressor genes promotes tumorgenesis and metastasis.2Site-specific methyltransferases have the same DNA target sequences as certain restriction enzymes. Methylation can also s

16、erve to protect DNA from enzymatic cleavage, since restriction enzymes are unable to bind and recognize externally modified sequences. This is especially useful in bacterial restriction modification systems that use restriction enzymes to cleave foreign DNA while keeping their own DNA protected by m

17、ethylation.Methylation of amino acids in the formation of proteins leads to more diversity of possible amino acids and, therefore, more diversity of function. The methylation reaction occurs on nitrogen atoms either on the N terminus or on the side-chain position of the protein and are usually irrev

18、ersible.翻譯起始因子：翻譯起始所必需的特異蛋白因子。與核糖體、信使核糖核酸、起始轉(zhuǎn)移核糖核酸等組成動(dòng)態(tài)翻譯起始復(fù)合體。真核和原核生物翻譯起始因子分別有eIF 16和IF 13等。Initiation factors起始因子（英語：）是指翻譯起始階段端結(jié)合到核糖體小亞基上的一些蛋白質(zhì)，翻譯是蛋白質(zhì)生物合成中的一部分。house-keeping genes持家基因()：又稱管家基因，是指所有細(xì)胞中均要穩(wěn)定表達(dá)的一類基因，其產(chǎn)物是對維持細(xì)胞基本生命活動(dòng)所必需的。如微管蛋白基因、糖酵解酶系基因與核糖體蛋白基因等。HSP：英文全稱為：heat shock protein，中文名為：熱休克蛋白，屬

19、于應(yīng)激反應(yīng)性蛋白，高溫應(yīng)激可誘導(dǎo)該蛋白質(zhì)形成。HSP是分子伴侶的一種，在蛋白質(zhì)翻譯后修飾過程中，起到促進(jìn)需要折疊的多肽鏈折疊為天然空間構(gòu)象的蛋白質(zhì)。genetic mapping遺傳作圖（）是指應(yīng)用遺傳學(xué)技術(shù)構(gòu)建能顯示基因以及其他序列特征在基因組上位置的圖。遺傳學(xué)技術(shù)包括雜交育種實(shí)驗(yàn)，對人類則是檢查家族史或系譜。與任何一種圖一樣，一個(gè)遺傳圖必須顯示出顯著特征的位置，在地理圖中，標(biāo)記是圖中可以識別的部分，如河流、道路以及建筑物。Gene mapping describes the methods used to identify the locus of a gene and the dista

20、nces between genes.Genome，基因組，一個(gè)細(xì)胞或者生物體所攜帶的一套完整的單倍體序列，包括全套基因和間隔序列。operon操縱子（）：指啟動(dòng)基因、操縱基因和一系列緊密連鎖的結(jié)構(gòu)基因的總稱。轉(zhuǎn)錄的功能單位。很多功能上相關(guān)的基因前后相連成串，由一個(gè)共同的控制區(qū)進(jìn)行轉(zhuǎn)錄的控制，包括結(jié)構(gòu)基因以及調(diào)節(jié)基因的整個(gè)DNA序列。主要見于原核生物的轉(zhuǎn)錄調(diào)控，如乳糖操縱子、阿拉伯糖操縱子、組氨酸操縱子、色氨酸操縱子等gene expression基因表達(dá)()是指細(xì)胞在生命過程中，把儲存在DNA順序中遺傳信息經(jīng)過轉(zhuǎn)錄和翻譯，轉(zhuǎn)變成具有生物活性的蛋白質(zhì)分子。Gene expression is

21、the process by which information from a gene is used in the synthesis of a functional gene product. These products are often proteins, but in non-protein coding genes such as transfer RNA (tRNA) or small nuclear RNA (snRNA) genes, the product is a functional RNA.效應(yīng)物_百度百科 是指能引起生理效應(yīng)的物質(zhì)。In biochemistry

22、, an effector molecule is usually a small molecule that selectively binds to a protein and regulates its biological activity. In this manner, effector molecules act as ligands that can increase or decrease enzyme activity, gene expression, or cell signalling. Effector molecules can also directly reg

23、ulate the activity of some mRNA molecules (riboswitches).In some cases, proteins can be considered to function as effector molecules, especially in cellular signal transduction cascades.The term effector is used in other fields of biology. For instance, the effector end of a neuron is the terminus w

24、here an axon makes contact with the muscle or organ that it stimulates or suppresses.跳躍基因或轉(zhuǎn)座子:一段可以從原位上單獨(dú)復(fù)制或斷裂下來，環(huán)化后插入另一位點(diǎn)，并對其后的基因起調(diào)控作用的DNA序列。Denaturation (biochemistry)Denaturation is a process in which proteins or nucleic acids lose the quaternary structure, tertiary structure and secondary structu

25、re which is present in their native state, by application of some external stress or compound such as a strong acid or base, a concentrated inorganic salt, an organic solvent (e.g., alcohol or chloroform), radiation or heat.3 If proteins in a living cell are denatured, this results in disruption of

26、cell activity and possibly cell death. Protein denaturation is also a consequence of cell death.45 Denatured proteins can exhibit a wide range of characteristics, from conformational change and loss of solubility to aggregation due to the exposure of hydrophobic groups.乳糖操縱子：大腸桿菌中與乳糖代謝功能相關(guān)的基因成鏃的串聯(lián)在一

27、起共同組成一個(gè)轉(zhuǎn)錄單位即乳糖操縱子，包括：Z 、Y 及A三個(gè)結(jié)構(gòu)基因，一個(gè)操縱序列O ,一個(gè)啟動(dòng)序列P及一個(gè)調(diào)節(jié)基因I。 增強(qiáng)子：增強(qiáng)子是能夠結(jié)合特異基因調(diào)節(jié)蛋白，促進(jìn)鄰近或遠(yuǎn)處特定基因表達(dá)的DNA序列。增強(qiáng)子距轉(zhuǎn)錄起始點(diǎn)的距離變化很大，但總是作用于最近的啟動(dòng)子。前導(dǎo)序列：存在于原核生物，為編碼區(qū)之前的不翻譯的mRNA區(qū)段，是mRNA區(qū)段類型。在原核生物中，一條mRNA分子常常編碼數(shù)種不同的多肽鏈。這種多順反子mRNA的頭一條多肽鏈合成的起點(diǎn)，同RNA分子的5P末端間的距離可達(dá)數(shù)百個(gè)核苷酸，這段編碼區(qū)之前的不翻譯的mRNA區(qū)段，叫做前導(dǎo)序列。Klenow片段：又名DNA聚合酶I（DNA pol

28、 1）大片段（克列諾片段，Klenow fragment，或稱克列諾酶，Klenow enzyme）：E.coli DNA聚合酶經(jīng)胰蛋白酶或枯草桿菌蛋白酶部分水解生成的C末端605個(gè)氨基酸殘基片段。該片段保留了DNA聚合酶I的5-3聚合酶和3-5外切酶活性，但缺少完整酶的5-3外切酶活性。DNA聚合酶 I（DNA-pol I）斷開后的存在另一個(gè)323個(gè)氨基酸殘基片段，保留5-3外切酶活性。terminator終止子(T)是給予RNA聚合酶轉(zhuǎn)錄終止信號的DNA序列。在一個(gè)操縱元中至少在構(gòu)基因群最后一個(gè)基因的后面有一個(gè)終止子。In genetics, a transcription termina

29、tor is a section of nucleic acid sequence that marks the end of a gene or operon in genomic DNA during transcription. This sequence mediates transcriptional termination by providing signals in the newly synthesized mRNA that trigger processes which release the mRNA from the transcriptional complex.

30、These processes include the direct interaction of the mRNA secondary structure with the complex and/or the indirect activities of recruited termination factors. Release of the transcriptional complex frees RNA polymerase and related transcriptional machinery to begin transcription of new mRNAs.作為起始信

31、號的密碼子稱為起始密碼子。silencer沉默子（）也稱為沉默子元件，是真核基因中的一種特殊的序列，與增強(qiáng)子有許多類似之處。按功能特性，真核基因順式作用元件可以分為啟動(dòng)子，增強(qiáng)子和沉默子。沉默子能夠同反式因子結(jié)合從而阻斷增強(qiáng)子及反式激活因子的作用，并最終抑制該基因的轉(zhuǎn)錄活性。弱化子attenuator，是指原核生物的操縱子中可以明顯衰減乃至終止轉(zhuǎn)錄作用的一段核苷酸序列，位于操縱子的上游。An insulator is a genetic boundary element that blocks the interaction between enhancers and promoters.It

32、 is thought that an insulator must reside between the enhancer and promoter to inhibit their subsequent interactions. Insulators therefore determine the set of genes an enhancer can influence. The need for insulators arises where two adjacent genes on a chromosome have very different transcription p

33、atterns; it is critical that the inducing or repressing mechanisms of one do not interfere with the neighbouring gene.1 Insulators have also been found to cluster at the boundaries of topologically associating domains (TADs) and may have a role in partitioning the genome into chromosome neighborhood

34、s - genomic regions within which regulation occurs.23Insulator activity is thought to occur primarily through the 3D structure of DNA mediated by proteins including CTCF.4 Insulated neighborhoods formed by physical interaction between two CTCF-bound DNA loci contain the interactions between enhancer

35、s and their target genes.5 順式作用元件.遺傳學(xué)：一種長約數(shù)百個(gè)核苷酸對,通常位于啟動(dòng)子正調(diào)控元件或負(fù)調(diào)控元件之間的一種調(diào)控序列.primosome引發(fā)體（）是DNA復(fù)制過程中的一種負(fù)責(zé)專一性引發(fā)的多酶復(fù)合物，位于復(fù)制叉的前端，能夠生成后隨鏈岡崎片段合成必需的RNA引物，主要成分為引物酶（如DnaG）以及DNA解旋酶（如DnaB）等。editosome編輯體；英文名稱：；定義1：進(jìn)行RNA轉(zhuǎn)錄物編輯的一個(gè)復(fù)雜系統(tǒng)。除了有許多酶之外，還有一個(gè)指導(dǎo)RNA。spliceosome剪接體（英文：）是指進(jìn)行RNA剪接時(shí)形成的多組分復(fù)合物，其大小為60S，主要是由小分子的核RNA

36、和蛋白質(zhì)組成。A spliceosome is a large and complex molecular machine found primarily within the splicing speckles of the cell nucleus of eukaryotic cells. The spliceosome is assembled from snRNAs and protein complexes. The spliceosome removes introns from a transcribed pre-mRNA, a type of primary transcrip

37、t. This process is generally referred to as splicing.1 Only eukaryotes have spliceosomes and some organisms have a second spliceosome, the minor spliceosome.2 An analogy is a film editor, who selectively cuts out irrelevant or incorrect material (equivalent to the introns) from the dailies and sends

38、 the cleaned-up version to be screened for the producer.HTH；最早在原核基因的激活蛋白和阻遏蛋白中發(fā)現(xiàn)的調(diào)控蛋白, 是一種同型二聚體。In proteins, the helix-turn-helix (HTH) is a major structural motif capable of binding DNA. It is composed of two helices joined by a short strand of amino acids and is found in many proteins that regulat

39、e gene expression. It should not be confused with the helix-loop-helix domain.1 basic helix-loop-helix DNA-binding domainBasic helix-loop-helix structural motif ofARNT. Two-helices(blue) are connected by a shortloop(red).1Stringent response嚴(yán)緊反應(yīng)：當(dāng)細(xì)菌在缺乏合成蛋白質(zhì)所必須的氨基酸時(shí)，停止合成核糖體RNA的反應(yīng)。From Wikipedia, the f

40、ree encyclopediaThe stringent response, also called stringent control, is a stress response of bacteria and plant chloroplasts in reaction to amino-acid starvation,1 fatty acid limitation,2 iron limitation,3 heat shock4 and other stress conditions. The stringent response is signaled by the alarmone

41、(p)ppGpp, and modulates transcription of up to 1/3 of all genes in the cell. This in turn causes the cell to divert resources away from growth and division and toward amino acid synthesis in order to promote survival until nutrient conditions improve.In Escherichia coli, (p)ppGpp production is media

42、ted by the ribosomal protein L11 (rplK resp. relC) and the ribosome-associated (p)ppGpp synthetase I, RelA; deacylated tRNA bound in the ribosomal A-site is the primary induction signal.1 RelA converts GTP and ATP into pppGpp by adding the pyrophosphate from ATP onto the 3 carbon of the ribose in GT

43、P, releasing AMP. pppGpp is converted to ppGpp by the gpp gene product, releasing Pi. ppGpp is converted to GDP by the spoT gene product, releasing pyrophosphate (PPi). GDP is converted to GTP by the ndk gene product. Nucleoside triphosphate (NTP) provides the Pi, and is converted to Nucleoside diph

44、osphate (NDP).In other bacteria, the stringent response is mediated by a variety of RelA/SpoT Homologue (RSH) proteins,5 with some having only synthetic, or hydrolytic or both (Rel) activities.6During the stringent response, (p)ppGpp accumulation affects the resource-consuming cell processes replica

45、tion, transcription, and translation. (p)ppGpp is thought to bind RNA polymerase and alter the transcriptional profile, decreasing the synthesis of translational machinery (such as rRNA and tRNA), and increasing the transcription of biosynthetic genes.7 Additionally, the initiation of new rounds of

46、replication is inhibited and the cell cycle arrests until nutrient conditions improve.8 Translational GTPases involved in protein biosynthesis are also affected by ppGpp, with Initiation Factor 2 (IF2) being the main target.9Chemical reaction catalyzed by RelA:ATP + GTP AMP + pppGppChemical reaction

47、 catalyzed by SpoT:ppGpp GDP + PPi or pppGpp - GTP + PPiExtensive Mendeley collection of scientific papers covering stringent response is available here.Molecular biologyMolecular biology /mlkjlr/ concerns the molecular basis of biological activity between biomolecules in the various systems of a ce

48、ll, including the interactions between DNA, RNA, and proteins and their biosynthesis, as well as the regulation of these interactions.1 Writing in Nature in 1961, William Astbury described molecular biology as:.not so much a technique as an approach, an approach from the viewpoint of the so-called b

49、asic sciences with the leading idea of searching below the large-scale manifestations of classical biology for the corresponding molecular plan. It is concerned particularly with the forms of biological molecules and . is predominantly three-dimensional and structuralwhich does not mean, however, th

50、at it is merely a refinement of morphology. It must at the same time inquire into genesis and function.2Life is a characteristic distinguishing physical entities having biological processes, such as signaling and self-sustaining processes, from those that do not, either because such functions have c

51、eased, or because they never had such functions and are classified as inanimate. Various forms of life exist, such as plants, animals, fungi, protists, archaea, and bacteria. The criteria can at times be ambiguous and may or may not define viruses, viroids, or potential artificial life as living. Bi

52、ology is the primary science concerned with the study of life, although many other sciences are involved.The definition of life is controversial. The current definition is that organisms maintain homeostasis, are composed of cells, undergo metabolism, can grow, adapt to their environment, respond to

53、 stimuli, and reproduce. However, many other biological definitions have been proposed, and there are some borderline cases of life, such as viruses. Throughout history, there have been many attempts to define what is meant by life and many theories on the properties and emergence of living things,

54、such as materialism, the belief that everything is made out of matter and that life is merely a complex form of it; hylomorphism, the belief that all things are a combination of matter and form, and the form of a living thing is its soul; spontaneous generation, the belief that life repeatedly emerg

55、es from non-life; and vitalism, a now largely discredited hypothesis that living organisms possess a life force or vital spark. Modern definitions are more complex, with input from a diversity of scientific disciplines. Biophysicists have proposed many definitions based on chemical systems; there ar

56、e also some living systems theories, such as the Gaia hypothesis, the idea that the Earth itself is alive. Another theory is that life is the property of ecological systems, and yet another is elaborated in complex systems biology, a branch or subfield of mathematical biology. Abiogenesis describes

57、the natural process of life arising from non-living matter, such as simple organic compounds. Properties common to all organisms include the need for certain core chemical elements to sustain biochemical functions.Life on Earth first appeared as early as 4.28 billion years ago, soon after ocean form

58、ation 4.41 billion years ago, and not long after the formation of the Earth 4.54 billion years ago.1234 Earths current life may have descended from an RNA world, although RNA-based life may not have been the first. The mechanism by which life began on Earth is unknown, though many hypotheses have been formulated and are often based on the MillerUrey experiment. The earliest known life forms are microfossils of bacteria. In July 2016, scientists reported identifying a set of 355 genes believed to be present in the last universal common ancestor (LUC