TK基因可编码胸苷激酶

04July2024GeneticEngineering1DNAisthegeneticmaterialStructureandcharacteristicsofDNANucleicacidshybridizebybasepairingMutationschangethesequenceofDNAGeneticinformationcanbeprovidedbyDNAorRNATheinterruptedgeneOrganizationandcharacteristicsofinterruptedgenesThecharacteristicsofexonsandintronsGenescanbeisolatedbytheconservationofexonsSomeDNAsequencescodeformorethanoneproteinSummarize04July2024GeneticEngineering2DNA是遗传物质DNA结构和特点通过碱基配对进行核酸杂交DNA的突变遗传信息可由DNA或RNA提供断裂基因

断裂基因的组成和结构外显子和内含子特点通过外显子的特点可分离基因一些DNA序列可编码一种以上蛋白本章主要内容04July2024GeneticEngineering31.1

Introduction引言04July2024GeneticEngineering41.1

Introduction引言Figure1.2showsthebasicthemeofthischapter.AgeneisasequenceofDNAthatproducesanothernucleicacid,RNA.TheDNAhastwostrandsofnucleicacid,andtheRNAhasonlyonestrand.ThesequenceoftheRNAisdeterminedbythesequenceoftheDNA,theRNAisinturnusedtodirectproductionofaprotein.04July2024GeneticEngineering51.2DNAisthegeneticmaterialDNAisthegeneticmaterialofbacteriaDNAisthegeneticmaterialofvirusesDNAisthegeneticmaterialofanimalcells04July2024GeneticEngineering61.2DNA是遗传物质DNA是细菌的遗传物质DNA是病毒的遗传物质DNA是动物细胞的遗传物质04July2024GeneticEngineering7Background背景肺炎链球菌：可引起肺炎，其荚膜多糖成分可以引发毒性。其有多种变异及亚型，其中S（smooth,S）亚型的荚膜具有多糖成分，而R（rough,R）亚型由于荚膜当中缺乏多糖成分所以不会导致毒性。ThebacteriumPneumococcus

肺炎链球菌属

killsmicebycausingpneumonia肺炎.Thesebacteriahaveasmoothtype(S)andaroughtype(R).TheStypecankillthemice,butRtypecannot.DNAisthegeneticmaterialofbacteria04July2024GeneticEngineering8EvidenceofDNAisthegeneticmaterialofbacteria04July2024GeneticEngineering9DNA是细菌的遗传物质证据04July2024GeneticEngineering10Avirulentmutants

无效突变ofavirushavelostthecapacity能力toinfectahostcellproductively有效的,thatis,tomakemorevirus.

Transfection

转染ofeukaryotic

真核cellsistheacquisition

获得ofnewgeneticmarkersbyincorporation

混合ofaddedDNA.

Transformingprinciple

转化原理isDNAthatistakenupbyabacteriumandwhoseexpressionthenchangestheproperties

性质oftherecipientcell.受体细胞DNAisthegeneticmaterialofvirusesSummary04July2024GeneticEngineering111.病毒的无效突变能够有效使其丧失感染宿主细胞的能力，但不会影响其在宿主细胞复制产生病毒。

2.通过转染的方式，能够将外源DNA转入至真核细胞内，使其获得一个新的基因标记。

3.转化的原理是：携带有新DNA的菌体在表达过程中会产生DNA所编码的蛋白，从而改变原有受体细胞的表达特性，形成一个新的个体。DNA是细菌的遗传物质小结04July2024GeneticEngineering12DNAisthegeneticmaterialofbacteriaKeyconceptsBacterialtransformationprovidedthefirstproof

证据thatDNAisthegeneticmaterial.

Geneticproperties

遗传特性canbetransferredfromonebacterialstrain

株（菌）toanotherbyextractingDNAfromthefirststrainandaddingittothesecondstrain.04July2024GeneticEngineering13DNA是细菌的遗传物质关键概念

细菌转化实验为DNA是遗传物质提供了重要的证据。从第一个菌株抽屉DNA,然后加入到第二个菌株中，能使遗传特性从一个细菌菌株传递到另一个菌株。04July2024GeneticEngineering14BackgroundDNAisthegeneticmaterialofvirusesAttaches:吸附Injected:注入Synthesis:合成Assembly:装配Release:释放04July2024GeneticEngineering15EvidenceofDNAisthegeneticmaterialofviruses04July2024GeneticEngineering161.BacteriawereinfectedwithT2phages

噬菌体thathadbeenradioactively

放射性的labeled

标记eitherintheirDNAcomponent

组分(with32P)orintheirproteincomponent(with35S).

2.Mostofthe32Plabelwaspresentintheinfectedbacteriaandlessthan1%oftheproteincontained35S.DNAisthegeneticmaterialofvirusesSummary04July2024GeneticEngineering171.利用32P和35S放射性同位素分别标记T2噬菌体的基因组DNA及外壳蛋白。

2.在子代噬菌体当中发现约30%P放射性同位素标记物，而在外壳蛋白中只有少于1%的S放射性同位素标记。

DNA是病毒的遗传物质小结04July2024GeneticEngineering18DNAisthegeneticmaterialofvirusesKeyconceptsPhageinfectionprovedthatDNAisthegeneticmaterialofviruses病毒.WhentheDNAandproteincomponentsofbacteriophages噬菌体

arelabeledwithdifferentradioactiveisotopes放射性同位素,onlytheDNAistransmittedtotheprogenyphages

子代噬菌体producedbyinfectingbacteria.04July2024GeneticEngineering19DNA是病毒的遗传物质关键概念

噬菌体感染证明DNA是病毒的遗传物质。当细菌的DNA和蛋白组分被标记上不同的放射性同位素时，仅有DNA被传递到感染细菌所产生的子代噬菌体当中。04July2024GeneticEngineering20DNA是动物细胞的遗传物质Background背景

TK基因可编码胸苷激酶，缺少TK基因的细胞自身无法合成胸苷，缺少TK基因的细胞无法在无胸苷的培养基中存活。

Thymidinekinase

胸苷激酶wasencoded编码byTKgene,thecellthatlack缺少TKgencannotsurvival

存活

inabsenceof

缺乏thymidine.04July2024GeneticEngineering21Evidenceof

DNAisthegeneticmaterialofanimalcells04July2024GeneticEngineering22WhenDNAisaddedtopopulations

群体ofsingleeukaryotic

真核cellsgrowinginculture培养基,thenucleicacidentersthecells,andinsomeofthemresults导致intheproductionofnewproteins.

DNAisthegeneticmaterialofvirusesSummary04July2024GeneticEngineering23DNA是动物细胞的遗传物质小结

当DNA加入到培养生长的单一真核生物细胞群体中，核酸可以进入细胞，有一些导致产生新的蛋白质，当使用纯化的DNA时，DNA整合到细胞中可以产生特殊的蛋白质。04July2024GeneticEngineering24DNAisthegeneticmaterialofanimalcellsKeyconceptsDNAcanbeusedtointroducenewgeneticfeatures

遗传特征intoanimalcellsorwholeanimals.Thegeneralprincipleofthenatureofthegeneticmaterial,then,isthatitisalwaysnucleicacid;infact,itisDNAexceptintheRNAviruses.04July2024GeneticEngineering25DNA是动物细胞的遗传物质关键概念

利用DNA可引入新的特性给动物细胞或整个动物。原则上，遗传物质的本质是核酸，事实上除了RNA病毒之外，其余生物的遗传物质都是DNA。04July2024GeneticEngineering261.3StructureandcharacteristicsofDNADNAisadoublehelix螺旋DNAreplication复制issemiconservative

半保留的Nucleicacidshybridize

杂交bybase

碱基pairing配对.04July2024GeneticEngineering271.3DNA的结构及特点DNA是双螺旋结构DNA复制是半保留复制核酸通过碱基配对进行杂交04July2024GeneticEngineering28核酸相关基础知识核酸

nucleicacid核苷酸

nucleotide核苷

nucleoside磷酸

phosphate嘌呤碱

purinebase或嘧啶碱

pyrimidinebase（碱基

base）核糖

ribose或脱氧核糖

deoxyribose（戊糖

amylsugar）04July2024GeneticEngineering2904July2024GeneticEngineering3004July2024GeneticEngineering31DNAisadoublehelix04July2024GeneticEngineering32DNA是双螺旋结构04July2024GeneticEngineering33DNAreplicationissemiconservativeEvidenceofDNAreplication复制issemiconservative

半保留04July2024GeneticEngineering34DNA是半保留复制BasepairingprovidesthemechanismforreplicatingDNA04July2024GeneticEngineering35ThereplicationforkistheregionofDNAinwhichthereisatransitionfromtheunwoundparentalduplextothenewlyreplicateddaughterduplexes.

DNAreplicationissemiconservativeReplicationfork复制叉04July2024GeneticEngineering36非复制区是母双体，而打开的双链部分是子双体的复制区，母双体在两个复制区间的位置打开，该区域被称之为复制叉。DNA是半保留复制04July2024GeneticEngineering371.Denaturation

变性ofDNAorRNAdescribesitsconversion

转变fromthedouble-stranded

股（链）tothesingle-strandedstate情况;separation

分离ofthestrandsismostoftenaccomplished

达到byheating.

2.Hybridization

杂交isthepairingo