Qhov sib txawv tseem ceeb ntawm CRISPR thiab txwv cov enzymes yog tias CRISPR yog ib qho tshwm sim ntawm kev tiv thaiv kab mob tiv thaiv kab mob uas tsis ntev los no tau siv rau eukaryotic noob kho thiab hloov kho thaum txwv cov enzymes yog cov txiab lom uas ua rau DNA molecules rau hauv cov khoom me.
Genome kho thiab hloov kho noob yog qhov nthuav thiab tshiab hauv cov noob caj noob ces thiab molecular biology. Cov kev tshawb fawb txog noob caj noob ces dav siv kev hloov kho noob. Tsis tas li ntawd, kev hloov pauv noob yog qhov tseem ceeb hauv kev txheeb xyuas cov khoom ntawm cov noob, kev ua haujlwm ntawm cov noob thiab yuav ua li cas hloov pauv hauv cov noob tuaj yeem cuam tshuam rau nws txoj haujlwm. Nws yog ib qho tseem ceeb kom tau txais txoj hauv kev ua tau zoo thiab txhim khu kev qha los ua kom meej, cov hom phiaj hloov pauv mus rau genome ntawm cov hlwb nyob. CRISPR thiab kev txwv enzymes ua lub luag haujlwm tseem ceeb hauv kev hloov pauv noob. CRISPR hloov cov noob nrog kev ua haujlwm siab. Kev txwv cov enzymes ua haujlwm li cov txiab lom uas ua rau DNA molecules rau hauv cov khoom me me.
CRISPR yog dab tsi?
Lub CRISPR system yog lub hauv paus ntsiab lus ntawm qee cov kab mob xws li E. coli thiab Archea. Nws yog kev tiv thaiv kev tiv thaiv kab mob tiv thaiv txawv teb chaws DNA-raws li ntxeem tau. Tsis tas li ntawd, nws yog ib qho kev sib txuas lus tshwj xeeb. CRISPR system muaj ntau yam DNA rov ua dua. Cov ntsiab lus no cuam tshuam nrog luv luv "spacer" ib ntus muab los ntawm txawv teb chaws DNA thiab ntau yam Cas noob. Qee cov Cas genes yog nucleases. Yog li, lub cev tiv thaiv kab mob tag nrho yog hu ua CRISPR/Cas system.
Lub CRISPR / Cas system ua haujlwm hauv plaub kauj ruam:
- Lub kaw lus genetic tethering invading phage thiab plasmid DNA ntu (spacers) rau hauv CRISPR loci (hu ua spacer acquisition step).
- crRNA maturation kauj ruam - Tus tswv tsev sau thiab ua cov txheej txheem CRISPR loci los tsim kom muaj CRISPR RNA (crRNA) uas muaj ob qho tib si CRISPR rov hais dua thiab cov khoom sib xyaw ua ke.
- CrRNA kuaj pom homologous DNA sib lawv liag los ntawm kev sib txuas ua ke. Qhov no tseem ceeb heev thaum muaj tus kab mob tshwm sim thiab muaj tus kab mob kis.
- Target interference kauj ruam - crRNA kuaj DNA txawv teb chaws, tsim ib qho nyuaj nrog txawv teb chaws DNA thiab tiv thaiv tus tswv tsev tiv thaiv cov DNA txawv teb chaws.
Tam sim no, CRISPR/Cas9 system yog siv los hloov lossis hloov cov genome ntawm cov tsiaj nyeg los ntawm kev thim rov qab los yog ua kom muaj zog. Cov kab mob mammalian tuaj yeem teb rau CRISPR/Cas9 kho DNA so los ntawm kev siv cov txheej txheem kho. Nws tuaj yeem ua tiav los ntawm kev siv tsis yog homologous kawg koom nrog txoj kev (NHEJ) lossis homology-directed kho (HDR). Ob qho kev kho cov txheej txheem no coj qhov chaw los ntawm kev nthuav qhia ob txoj hlua khi. Qhov no ua rau mammalian gene kho. NHEJ tuaj yeem ua rau ablation ntawm cov noob hloov pauv thiab tuaj yeem siv los tsim kev poob haujlwm. HDR tuaj yeem siv los qhia txog kev hloov pauv tshwj xeeb lossis qhia txog DNA ntu ntawm qhov ntev sib txawv. Tam sim no, CRISPR / Cas system yog siv rau hauv kev kho mob, biomedical, kev ua liaj ua teb thiab kev tshawb fawb.
Kev txwv Enzymes yog dab tsi?
Ib txwv enzyme, feem ntau hu ua kev txwv endonuclease, muaj peev xwm txiav DNA molecules rau hauv me me. Cov txheej txheem cleaving tshwm sim nyob ze lossis ntawm qhov chaw paub tshwj xeeb ntawm DNA molecule hu ua qhov chaw txwv. Ib qhov chaw lees paub feem ntau yog tsim los ntawm 4-8 lub hauv paus khub. Nyob ntawm qhov chaw ntawm cleavage, txwv enzymes tuaj yeem yog plaub (04) ntau hom: Hom I, Hom II, Hom III thiab Hom IV. Lwm yam tshaj li qhov chaw ntawm kev sib cais, yam xws li muaj pes tsawg leeg, qhov yuav tsum tau muaj ntawm co-factors thiab cov xwm txheej ntawm lub hom phiaj sib lawv liag tau muab rau hauv kev txiav txim siab thaum sib txawv txwv cov enzymes rau hauv plaub pawg.
Thaum lub sijhawm tawg ntawm DNA molecules, qhov chaw cleaving tuaj yeem nyob ntawm qhov chaw txwv nws tus kheej lossis nyob deb ntawm qhov chaw txwv. Kev txwv enzymes tsim ob qhov kev txiav los ntawm txhua qhov qab zib-phosphate qaum qaum hauv ob lub helix ntawm DNA.
Daim duab 02: Kev txwv Enzymes
txwv tsis pub enzymes feem ntau pom muaj nyob hauv Achaea thiab kab mob. Lawv siv cov enzymes no los ua cov txheej txheem tiv thaiv tawm tsam cov kab mob invading. Cov kev txwv enzymes tshem tawm txawv teb chaws (pathogenic) DNA tab sis tsis yog lawv tus kheej DNA. Lawv tus kheej DNA tiv thaiv los ntawm ib qho enzyme hu ua methyltransferase, uas ua rau kev hloov kho hauv tus tswv DNA thiab tiv thaiv kev tawg.
Type I txwv enzyme muaj qhov chaw cleaving uas nyob deb ntawm qhov chaw lees paub. Kev ua haujlwm ntawm cov enzyme xav tau ATP thiab cov protein, S-adenosyl-L-methionine. Hom I txwv enzyme yog suav tias yog kev ua haujlwm ntau vim muaj ob qho kev txwv thiab kev ua methylase. Hom II txwv enzymes cleave nyob rau hauv qhov chaw paub nws tus kheej los yog nyob ze rau nws. Nws tsuas yog xav tau magnesium (Mg) rau nws txoj haujlwm. Hom II txwv enzymes tsuas muaj ib qho kev ua haujlwm thiab muaj kev ywj pheej ntawm methylase.
Dab tsi yog qhov zoo sib xws ntawm CRISPR thiab txwv Enzymes?
- CRISPR thiab txwv cov enzymes yog cov cuab yeej tseem ceeb hauv kev hloov pauv noob.
- Ib feem ntawm CRISPR lossis Cas9 thiab txwv cov enzymes yog endonucleases.
- Ob leeg tuaj yeem paub cov yam ntxwv DNA ua ntu zus thiab tshem DNA.
- Lawv muaj cov kab mob thiab archaea.
- Ob leeg CRISPR thiab txwv cov enzymes yog cov kab ke tshwj xeeb.
Qhov txawv ntawm CRISPR thiab Kev txwv Enzymes yog dab tsi?
CRISPR-Cas system yog lub cev tiv thaiv kab mob prokaryotic uas ua rau muaj kev tiv thaiv kab mob txawv teb chaws. Ntawm qhov tod tes, txwv tsis pub enzymes yog endonucleases uas paub txog ib ntu ntawm nucleotides thiab tsim ib qho kev txiav ob zaug hauv DNA. Yog li, qhov no yog qhov sib txawv tseem ceeb ntawm CRISPR thiab txwv enzymes.
Ntxiv mus, CRISPR- tso cai rau kev txiav kom meej heev. Hauv kev sib piv rau qhov ntawd, txwv tsis pub enzyme cleavage tsawg dua. Tsis tas li ntawd, CRISPR yog cov txheej txheem siab heev thaum kev txwv cov enzymes yog qhov qub.
Hauv qab infographic qhia txog qhov sib txawv ntawm CRISPR thiab txwv enzymes.
Summary – CRISPR vs Restriction Enzymes
CRISPR thiab txwv cov enzymes yog ob hom kev siv hauv kev hloov pauv noob. CRISPR yog kev tiv thaiv kev tiv thaiv kab mob ua rau qee cov kab mob tawm tsam DNA txawv teb chaws raws li kev cuam tshuam. Nws yog ib tug natural tiv thaiv mechanism. Hauv qhov sib piv, txwv tsis pub enzymes yog endonucleases uas cleave ob-stranded DNA. Ob leeg CRISPR thiab txwv enzymes muaj peev xwm txiav DNA rau hauv me me. Txawm li cas los xij, ob qho tib si yog ib ntus tshwj xeeb. Hauv kev sib piv rau CRISPR, kev txwv enzymes yog qhov tseem ceeb. CRISPR tso cai rau kev txiav txim siab heev tshaj qhov txwv enzymes. Yog li, qhov no yog cov ntsiab lus ntawm qhov sib txawv ntawm CRISPR thiab txwv enzymes.
