Qhov sib txawv tseem ceeb ntawm tus neeg txhawb nqa thiab tus neeg tawm tsam yog lawv txoj haujlwm. Tus activator pab txhawb kev txhawb nqa ntawm cov txheej txheem kev hloov pauv los ntawm kev khi rau kev txhim kho, thaum tus txhawb nqa yog qhov chaw ntawm RNA polymerase khi, thiab kev pib sau ntawv yuav tshwm sim, thiab tus neeg tawm tsam downregulates transcription los ntawm khi rau silencers.
Kev txhais lus yog txheej txheem ntawm kev sib txuas ua ke mRNA siv tus qauv DNA. Cov txheej txheem tshwm sim nyob rau hauv lub nucleus hauv eukaryotes, thaum nyob rau hauv prokaryotes, nws tshwm sim nyob rau hauv lub cytoplasm. Transcription muaj peb theem tseem ceeb: pib, elongation, thiab termination. Cov activators thiab cov neeg tawm tsam tswj hwm kev pib hloov pauv, thaum cov neeg txhawb nqa tseem ceeb hauv kev khi ntawm RNA polymerase. RNA polymerase yog lub ntsiab enzyme uas kho cov kev hloov pauv.
Tus Activator yog dab tsi?
Activator yog qhov hloov pauv hloov pauv uas khi rau thaj chaw txhim kho kom txhim kho kev sau ntawv. Thaum ua tiav, nws ua rau muaj kev hloov pauv hauv kev taw qhia ntawm cov qauv strand, ua kom muaj zog lossis txhawb kev hloov pauv. Tsis tas li ntawd, nws yuav txhawb nqa txoj kev khi ntawm RNA polymerase rau qhov chaw txhawb nqa los pib sau ntawv.
Daim duab 01: Tus Ua Haujlwm
Activators feem ntau yog cov protein molecules. Lawv txhawb txoj kev anabolic ntawm cov noob qhia. Activator muaj nuj nqi yog feem ntau pom nyob rau hauv eukaryotic transcriptional regulation.
Tus Promoter yog dab tsi?
Lub cheeb tsam txhawb nqa ntawm cov noob yog thaj tsam uas RNA polymerase khi tau tshwm sim thaum pib ntawm kev sau ntawv. Cov cheeb tsam txhawb nqa hauv prokaryotes thiab eukaryotes sib txawv. Kev txhawb nqa kev ua kom muaj zog yog ib kauj ruam tseem ceeb hauv kev tswj hwm thiab ua kom muaj zog. Cov cheeb tsam txhawb nqa Prokaryotic yog tam sim no nyob rau hauv -35 thiab -10 cheeb tsam upstream ntawm qhov chaw pib transcription. Lub cheeb tsam -10 txhawb nqa tseem hu ua TATA lub thawv lossis lub thawv pribnow. Lub sigma qhov tseem ceeb ntawm cov kab mob RNA polymerase paub txog tus txhawb nqa thiab khi los tsim cov kev txhawb nqa kaw. Lub unwinding ntawm ob strands yuav tshwm sim tom ntej, ua rau ib tug qhib kev txhawb nqa complex. Thaum kawg, qhov ua tau zoo ntawm RNA polymerase tawm pib qhov kev hloov pauv.
Daim duab 02: Tus Txhawb Nqa
Nyob rau hauv eukaryotes, kev txhawb nqa kev ua haujlwm tshwm sim los ntawm ntau yam kev pib pib. Muaj ob hom kev txhawb nqa tseem ceeb hauv eukaryotes. Lawv yog TATA-tsawg txhawb nqa thiab TATA txhawb nqa.
Tus neeg ntxeev siab yog dab tsi?
Tus neeg tawm tsam yog qhov kev hloov pauv uas txo qis cov txheej txheem ntawm kev sau ntawv los ntawm kev khi rau thaj tsam ntsiag to. Qhov no tiv thaiv kev khi ntawm RNA polymerase rau tus txhawb nqa. Qhov no yog lub luag haujlwm tseem ceeb ntawm lub xovtooj ntawm tes kom tsis txhob muaj kev hloov pauv. Ntawm no, tus neeg tawm tsam khi rau thaj tsam ntsiag to thiab thaiv cov txheej txheem ntawm kev sau ntawv los ntawm kev txo tus nqi thiab nres tag nrho cov txheej txheem.
Daim duab 03: Tus neeg ntxeev siab
Cov neeg tawm tsam kev tawm tsam teb rau cov stimuli sab nraud. Qhov no tseem tiv thaiv kev khi ntawm activator promoters rau cov cheeb tsam txhawb nqa. Corepressors yog ib pawg ntawm cov neeg tawm tsam thiab kev tawm tsam kev hloov pauv los ntawm kev nrhiav neeg ua haujlwm ntawm histone deacetylase. Histone deacetylase tsub kom tus nqi zoo ntawm histone protein. Qhov no ntxiv dag zog rau kev sib cuam tshuam ntawm DNA thiab histones thiab txo qhov nkag tau ntawm DNA rau kev sau ntawv.
Dab tsi yog qhov zoo sib xws ntawm Tus Txhawb Txhawb Kev Txhawb Nqa thiab Kev Tawm Tsam?
- Cov neeg ua haujlwm, cov neeg txhawb nqa, thiab cov neeg tawm tsam tau koom nrog cov txheej txheem sau npe.
- Lawv lub luag haujlwm tseem ceeb yog thaum pib ntawm kev sau ntawv.
- Tsis tas li ntawd, lawv ua raws li kev tswj hwm kev cai lij choj.
- Txhua tus pab txhawb qhov raug khi ntawm RNA polymerase.
Dab tsi yog qhov txawv ntawm Activator Promoter thiab Repressor?
Activator pab txhawb kev tswj hwm ntawm cov txheej txheem kev hloov pauv los ntawm kev khi rau kev txhim kho. Lub caij no, RNA polymerase khi nrog thaj tsam txhawb nqa thaum lub sijhawm pib sau ntawv. Whereas, tus repressor downregulates cov txheej txheem transcription los ntawm khi rau silencers. Yog li, qhov no yog qhov sib txawv tseem ceeb ntawm activator promoter thiab repressor. Ntxiv mus, activators thiab repressors feem ntau yog cov proteins uas tswj kev hloov pauv thaum txhawb nqa yog ib qho tseem ceeb ntawm DNA tam sim no nyob rau hauv qhov chaw ntawm cov noob. Tsis tas li ntawd, ob qho tib si activators thiab cov neeg txhawb nqa txhim kho cov txheej txheem ntawm kev sau ntawv thaum cov neeg tawm tsam cuam tshuam cov txheej txheem ntawm kev sau.
Cov hauv qab no infographic nthuav tawm qhov sib txawv ntawm tus neeg txhawb nqa kev txhawb nqa thiab kev tawm tsam hauv daim ntawv teev npe rau ib sab ntawm kev sib piv.
Summary – Activator vs Promoter vs Repressor
Activator, txhawb nqa, thiab kev tawm tsam yog cov xwm txheej hloov pauv uas cuam tshuam rau tus nqi ntawm kev sau ntawv. Qhov sib txawv tseem ceeb ntawm tus activator txhawb nqa thiab tus neeg tawm tsam yog tias tus activator pab txhawb kev txhawb nqa ntawm cov txheej txheem kev hloov pauv los ntawm kev khi rau cov kev txhim kho, thaum tus txhawb nqa pab txhawb kev khi ntawm RNA polymerase thaum lub sijhawm pib sau ntawv thiab cov neeg tawm tsam downregulate transcription los ntawm kev khi rau silencers. Activators thiab repressors feem ntau yog cov protein molecules uas khi rau cov cheeb tsam tswj hwm hauv cov noob thiab ua rau kev hloov pauv hauv DNA. Cov neeg txhawb nqa yog qhov chaw nce toj. RNA polymerase binding tshwm sim ntawm qhov chaw txhawb nqa. Yog li, qhov no yog qhov txawv ntawm activator txhawb nqa thiab tus neeg tawm tsam.
