Name
¿À¿µ¹Î
2003-01-13 11:47:05 | Hit : 19755 | Vote : 1321
Subject
Purification of total cell DNA from living cells
Chapter3. Purification of DNA from living cells (»ì¾ÆÀÖ´Â ¼¼Æ÷¿¡¼ DNAÀÇ Á¤Á¦)
»ì¾ÆÀÖ´Â cell¿¡¼ DNA¸¦ ¾ò°íÀÚ ÇÏ´Â °ÍÀº ¾Æ·¡ÀÇ 3°¡ÁöÀÌ´Ù.
* total cell DNA : geneÀÌ cloneµÇ±â À§ÇÑ source material
* pure plasmid DNA
* phage DNA : phage DNA vehicle·Î »ç¿ëÇϱâ À§ÇØ
3.1. Preparation of total cell DNA ( Àüü ¼¼Æ÷ DNAÀÇ Áغñ)
Àü¹ÝÀûÀÎ ¼ø¼´Â ¾Æ·¡¿Í °°´Ù
¨ç bacteria cultureÀÇ grow¿Í harvest
¨è cellÀ» ±ú¶ß¸®°í ¿¾î content¸¦ release
¨é cell extract¿¡¼ DNA¸¸ Á¦¿ÜÇÏ°í ¸ðµç component Á¦°Å
¨ê DNA solutionÀ» concentrated ÇÑ´Ù.
(1) Growing and harvesting a bacterial culture (¹ÚÅ׸®¾Æ ÄÃóÀÇ ¼ºÀå°ú ¼öÈ®)
°ÅÀÇ ¸ðµç bacteria´Â liquid medium(broth culture)¿¡¼ º° ¾î·Á¿ò ¾øÀÌ Àß ÀÚ¶õ´Ù.
¨ç culture medium (ÄÃó¹èÁö)
culture mediumÀº bacteria°¡ ÀÚ¶ó°í È¿À²ÀûÀ¸·Î divideµÇµµ·Ï essential nutrientÀÇ ³óµµ°¡ balancedµÈ mixture·Î °ø±ÞµÇ¾î¾ß ÇÑ´Ù.
©± M9 : defined medium
* ¸ðµç component°¡ ¾Ë·ÁÁ® ÀÖ´Ù.
* nitrogen, magnesium, calcium °°Àº Çʼö element Á¦°øÀÇ inorganic nutrientÀÇ mixture Æ÷ÇÔ
* glucose : carbon°ú energy source
* bacterial growth¸¦ À§ÇØ trace element³ª vitamin °°Àº growth factor°¡ ÇÊ¿ä.
©² Luria-Bertani (LB) : undefined medium
±× componentsÀÇ identity¿Í quantity¸¦ ¸ð¸¥´Ù.
* tryptone : amino acid, small peptide
* yeast extract(ºÎºÐÀûÀ¸·Î digestµÈ yeast cellÀÇ dried preparation) : nitrogen requirement, sugar, inorganic, organic nutrients
¡æ bacteria growth¸¦ À§ÇØ ´õ ÀÌ»óÀÇ supplementationÀÌ ÇÊ¿ä¾ø´Ù.
¨è simple DNA source¸¦ ¾ò±â À§ÇÑ culture
¡æ complex medium(LB)°¡ Àû´ç
* LB medium¿¡¼ 37¢ªC rotary platform¿¡¼ 150 ~ 250 rpmÀÇ shaking
¡æ E.coli cellÀº 20ºÐ¸¶´Ù Çѹø¾¿ ºÐ¿, ¾à 2 ~ 3 x 10^9 cells/mlÀÇ maxium density¿¡ µµ´ÞÇÒ¶§±îÁö ÀÚ¶õ´Ù.
* cultureÀÇ growth ÃøÁ¤Àº 600 nmÀÇ optical density¸¦ ÃøÁ¤Çؼ ¾È´Ù.
¡æ 600 nm wave length¿¡¼ 1OD unitÀº 0.8 x 10^9 cells/ml
* cell extractÀÇ Áغñ
bacteria´Â °¡´ÉÇÑ small volumeÀ¸·Î ÃëÇÏ°í harvestingÀº culture¸¦ centrifugeÇؼ ÁغñÇÑ´Ù.
¡æ centrifugationÀÇ ¼Óµµ¸¦ Àû´çÈ÷ ³·Ã߸é bacteria pelletÀÇ tube ¾Æ·¡¿¡ À§Ä¡ÇÏ°í supertanent¿¡ À§Ä¡ÇÑ cuture media´Â µû¶ó¼ ¹ö¸°´Ù.
(2) Preparation of a cell extract (¼¼Æ÷ ÃßÃâ¹°ÀÇ Áغñ)
bacterial cellÀº cytoplasmic membrane¿¡ µé¾îÀÖ°í rigid cell wall¿¡ ÀÇÇØ µÑ·¯½×¿© ÀÖ´Ù.
ex) E,coli´Â cell wall ´ÙÀ½¿¡ 2Â÷·Î outer membraneÀÌ ÀÖ´Ù.
* bacterial cellÀ» ±ú´Â ¹æ¹ý
¨± physical method(¹°¸®Àû ¹æ¹ý) : mechanical force(±â°èÀû Èû)·Î cellÀ» ±ü´Ù
¨² chemical method(ÈÇÐÀû ¹æ¹ý) : cell barrier¿¡ ¿µÇâÀ» ÁÖ´Â chemical agent(ÈÇÐÀû ÀÎÀÚ)¿¡ ³ëÃâÇÏ¿© cellÀ» lysisÇÑ´Ù.
¡æ DNA preparation¿¡ ¸¹ÀÌ ¾²ÀÓ
* Chemical method(ÈÇÐÀû ¹æ¹ý)
chemical lysis(ÈÇÐÀû ºÐÇØ)
¨± cell wallÀ» °ø°ÝÇÏ´Â agent
¨² cell membraneÀ» ±ú´Â agent
ex) E.coli
** cell wall
lysozyme(¶óÀ̼ÒÀÚÀÓ) : cell wall rigidity(µüµüÇÑ ¼¼Æ÷º®)¸¦ À¯Áö½ÃÅ°´Â polymeric compound(Æú¸®¸Ó ±¸¼º¿ä¼Ò)¸¦ digest(ºÐÇØ)ÇÑ´Ù.
ethylenediamine tetraacetate(EDTA) : cell envelope(¼¼Æ÷¸¦ µÑ·¯½Î´Â) Àüü structure¸¦ À¯ÁöÇÏ´Â Çʼö magnesiumÀ» Á¦°ÅÇÑ´Ù. DNA¸¦ degrade(ºÐÇØ)ÇÏ´Â cellular enzyme(¼¼Æ÷ È¿¼Ò)À» inhibit(¹æÇØ)ÇÑ´Ù.
** detergent(¼¼Á¦) : sodium dodecyl sulphate (SDS)
lipid molecule(Áö¹æ ¼¼Æ÷ÀÇ ÀÏÁ¾)ÀÇ Á¦°Å·Î lysis(ºÐÇØ) °úÁ¤À» µ½°í cell membrane(¼¼Æ÷¸·)ÀÇ Æı«¸¦ À̲ö´Ù.
* insoluble cell debris(³ìÁö¾Ê´Â ¼¼Æ÷ÀÇ Â±â)ÀÇ Á¦°Å
ºÎºÐÀûÀ¸·Î digest(ºÐÇØ)µÈ cell wall fraction(¼¼Æ÷º® Á¶°¢) °°Àº compound´Â centrifugation(¿ø½ÉºÐ¸®)¿¡ ÀÇÇØ pelleted(¹¶Ãļ ¾Æ·¡¿¡ ½×ÀÓ)µÈ´Ù.
±×·¯¸é ºñ±³Àû clear supernatant(¸¼Àº »ó¾×Ãþ) °°Àº cell extract(¼¼Æ÷ ÃßÃâ¹°)°¡ ³²´Â´Ù.
(3) Purification of DNA from a cell extract (¼¼Æ÷ ÃßÃâ¹°¿¡¼ DNAÀÇ Á¤Á¦)
bacterial cell extract¿¡´Â protein, RNA, DNA°¡ µé¾îÀÖ´Ù.
¨ç cell extractÀÇ deproteinize(´Ü¹éÁú ºÐÇØ)
phenol°ú chloroformÀÇ 1:1 mixture¸¦ ÷°¡ÇÑ´Ù.
¡æ nucleic acid(DNA,RNA)¸¦ aqueous solution¿¡ ³²±â°í protein¸¸ °¡¶ó ¾ÉÈù´Ù.
* ¹æ¹ý
cell extract¸¦ solvent¿Í gently mixÇÏ°í centrifugation¿¡ ÀÇÇØ layer·Î ³ª´µ¾îÁø´Ù.
precipitated(ħÀüµÈ) protein moleculeÀÌ aqueous¿Í organic layer »çÀÌ¿¡ ÇϾá coagulated(½ÇŸ·¡Ã³·³ ¾ûŲ) mass·Î ³²´Â´Ù.
¡æ nucleic acidÀÇ aqueous solutionÀº pipette·Î ¿Å±ä´Ù.
¸¸¾à protein content°¡ ³Ê¹« Å©¸é single phenol extractionÀº nucleic acid·Î ¿Ïº®È÷ purifyÇϱ⿣ ÃæºÐÄ¡ ¾Ê´Ù.
¡æ phenol extraction½Ã mixing°ú centrifugation stepÀº DNA moleculeÀÇ ¼Õ»óÀ» °¡Á®¿Ã ¼ö ÀÖ¾î ¹Ýº¹»ç¿ëÀÌ ¾î·Æ´Ù.
¡Å phenol extraction Àü¿¡ proteinase K ³ª pronase°°Àº protease¸¦ cell extract¿¡ ó¸®
¡æ polypeptide¸¦ ÀÛÀº unitÀ¸·Î À߶ó phenol¿¡ ÀÇÇØ ½±°Ô Á¦°ÅµÇ°Ô ÇÑ´Ù.
** RNA¿¡¼ mRNA´Â phenol treatment·Î Á¦°Å°¡ µÇ³ª ±× ¿ÜÀÇ RNA´Â aqueous layer¿¡ ³²°ÔµÈ´Ù.
¡æ ribonuclease enzymeÀ» ½á¼ ribonucleotide subunitÀ¸·Î degrade(ºÐÇØ) ½ÃŲ´Ù.
(4) Concentration of DNA sample (DNA »ùÇÃÀÇ ³óÃà)
dilute solution(³óµµ°¡ ³·Àº ¿ë¾×)ÀÌ Á¾Á¾ ¾ò¾îÁö¹Ç·Î DNA ³óµµ¸¦ Áõ°¡½ÃÅ°´Â °ÍÀº Áß¿äÇÏ´Ù.
* Ethanol precipitation(¿¡Åº¿Ã ħÀü) ¹æ¹ý
salt(sodium ion Na+ °°Àº monovalent cation »óÅÂ)ÀÇ Á¸ÀçÇÏ¿¡ temperature -20¢ªC ÀÌÇÏ´Â absoulte ethanolÀº È¿°úÀûÀ¸·Î polymeric acid¸¦ ħÀü½ÃŲ´Ù.
glass podÀ̳ª centrifugationÀ¸·Î DNA moleculeÀ» ±¸ÇÔ
Ethanol precipitationÀº short-chain°ú monomeric nucleic acid component¸¦ solution¿¡ ³²±â¹Ç·Î À̶§ robonuclease treatment¿¡ ÀÇÇØ ribonucleotide(RNA)°¡ ¾ø¾îÁø´Ù.
(5) Measurement of DNA concentration (DNA ³óµµÀÇ ÃøÁ¤)
Ultraviolet(UV) absorbance spectrophotometry(¹æ»ç¼± Èí¼ö ÃøÁ¤±â)¿¡ ÀÇÇØ DNA ³óµµ°¡ ÃøÁ¤°¡´ÉÇÏ´Ù.
¡æ DNA solution¿¡ ÀÇÇØ Èí¼öµÈ UV radiation(¹æ»ç¼±)ÀÇ ¾çÀº sampleÀÇ DNA ¾ç¿¡ ºñ·ÊÇÑ´Ù.
wavelength(ÆÄÀå) 260nm¿¡¼ÀÇ absorbance(Èí¼öµµ) A260ÀÇ 1Àº ml´ç double stranded DNAÀÇ 50§¡¿¡ ÇØ´çÇÑ´Ù.
¡Å A260 1 = 50§¡/ml
* DNA preparationÀÇ purify ÃøÁ¤
A260/A280 < 1.8
¡æ DNA°¡ proteinÀ̳ª phenol¿¡ ÀÇÇØ ¿À¿°µÇ¾úÀ½À» ¾Ï½ÃÇÑ´Ù.
(6) Preparation of total cell DNA from organisms other than bacteria (¹ÚÅ׸®¾Æ°¡ ¾Æ´Ñ ´Ù¸¥ »ý¹°¿¡¼ÀÇ Àüü ¼¼Æ÷ DNAÀÇ Á¤Á¦)
»ç¿ëµÇ´Â cellÀÇ Æ¯º°ÇÑ ¼ºÁú¿¡ µû¶ó Á» modificationÀÌ µÈ ¹æ¹ýÀÌ ÇÊ¿äÇÏ´Ù.
¨ç Cell breakage stage(¼¼Æ÷¸¦ ±ú´Â ´Ü°è)¿¡ ÀÇÇÑ ¼öÁ¤ ÇÊ¿ä
chemicalÀÌ cellÀÇ Á¾·ù¿¡ µû¶ó ±â´ÉÀÇ Â÷ÀÌ°¡ ÀÖ´Ù.
¨è DNA¿¡¼ cellÀÇ extracted biochemical(»ýÈÇÐÀû) content(³»¿ë¹°)¿¡ ÀÇÇÑ ¼öÁ¤ ÇÊ¿ä
ex) most bacteria
cell extract ¡æ DNA(leave pure DNA sample), RNA(ribonuclease ó¸®ÇÏ¿© ¾ø¾Ú), protein(phenol extraction, protease treatment¿¡ ÀÇÇÑ Á¦°Å)
±×·¯³ª, plant tissue¿¡¼´Â »óȲÀÌ ´Ù¸£´Ù.
¸¹Àº ¾çÀÇ biochemical(carbohydrate) ¶§¹®¿¡ phenol extraction¿¡ ÀÇÇÑ Á¦°Å È¿À²ÀÌ ÀúÇϵȴÙ.
±×·¯¹Ç·Î ¾Æ·¡¿Í °°Àº ¹æ¹ýÀ» Ãß°¡ÇÑ ¼öÁ¤ÀÌ ÇÊ¿äÇÏ´Ù.
¨± Cetyltrimethylammonium(CTAB) detergent »ç¿ë ¡æ nucleic acid¿Í insoluble complex Çü¼º.
¡Å plant cell extract¿¡ CTAB¸¦ ÷°¡Çϸé, CTAB-nucleic acid complex°¡ ħÀüµÇ°í carbohydrate, protein, ´Ù¸¥ contaminant(¿À¿°¹°Áú)´Â supernatant(»ó¾×Ãþ)¿¡ ³²´Â´Ù.
precipitate(ħÀü¹°)´Â centrifugation(¿ø½ÉºÐ¸®)À¸·Î ¸ðÀ¸°í 1M NaCl·Î resuspendÇÏ°í complex¸¦ ±ü´Ù.
Ribonuclease treatment·Î RNA¸¦ Á¦°ÅÇÏ¿© pure plant DNA¸¦ ¾ò´Â´Ù.
¨² Guanidinium thiocyanate compound¸¦ Æ÷ÇÔÇÑ ¹æ¹ý
guanidinium thiocyanate´Â nucleic acid¸¦ Á¦¿ÜÇÑ ¸ðµç biochemicalÀ» denatureÇÏ°í dissolveÇÑ´Ù. ±×·¯¹Ç·Î ¾î¶² tissue typeÀÌ¶óµµ DNA release°¡ °¡´ÉÇÏ´Ù.
guanidinium thiocyanate Á¸ÀçÇÏ¿¡ DNA´Â silica particle¿¡ tightÇÏ°Ô bindÇÑ´Ù.
¡æ biochemicalÀÇ denatured mix¿¡¼ chromatography columnÀ» ÅëÇØ DNA¸¦ ½±°Ô ¾òÀ» ¼ö ÀÖ´Ù. columnÀÇ silica particle + DNA complex´Â ´Ê°Ô ³»·Á¿À°í ±× ¿Ü´Â »¡¸® ³»·Á¿À´Â °ÍÀ» ÀÌ¿ëÇÏ¿© ¾òÀº ´ÙÀ½, ¹°À» ÷°¡ÇÏ¿© DNA¿Í silica¿Í interactionÀ» ±ú¼ DNA¸¦ ¾ò´Â´Ù.
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