Qhov sib txawv tseem ceeb ntawm cis thiab trans splicing yog tias cis splicing yog ib qho intramolecular mechanism uas tshem tawm introns thiab koom nrog cov exons uas nyob rau hauv tib RNA transcript, thaum trans-splicing yog ib tug intermolecular mechanism uas tshem tawm introns los yog outrons thiab koom nrog cov exons uas tsis nyob hauv tib RNA cov ntawv sau tseg.
RNA splicing yog ib daim ntawv ntawm RNA ua ua ntej protein synthesis. Nyob rau hauv cov txheej txheem no, ib tug tshiab ua ntej-tus tub txib RNA transcript yog hloov mus rau ib tug paub tab tus tub txib RNA. Mature messenger RNA pab tsim cov protein molecule. Thaum lub sij hawm RNA splicing, cov introns (tsis-coding cheeb tsam) raug tshem tawm, thiab exons (coding regions) tau koom ua ke los ua mRNA paub tab. Cis thiab trans splicing yog ob hom RNA splicing mechanisms.
Cis Splicing yog dab tsi?
Cis splicing yog ib qho intramolecular mechanism uas tshem tawm cov introns thiab koom nrog cov exons uas nyob hauv tib RNA cov ntawv sau tseg. Ib txwm cis splicing txheej txheem ib leeg RNA molecule. Cis splicing yog cov txheej txheem splicing ntawm pre mRNA ua los ntawm spliceosomes. Nyob rau hauv lub intron, ib qho chaw pub dawb (5' kawg ntawm lub intron), ib ceg chaw (ze ntawm 3' kawg ntawm lub intron) thiab qhov chaw txais (3' kawg ntawm lub intron) yog qhov tseem ceeb heev rau kev sib txuas. Lub chaw pub dawb splice suav nrog qhov sib txawv tsis sib xws GU ntawm 5 'kawg ntawm qhov intron. Qhov chaw txais splice ntawm qhov kawg ntawm 3 'intron muaj qhov sib txawv ntawm AG ib ntus. Upstream los ntawm AG ib ntus, muaj ib cheeb tsam hu ua thaj av pyrimidine (polypyrimidine ib puag ncig). Ntxiv mus los ntawm cov kab mob polypyrimidine, muaj ib ceg taw tes uas suav nrog adenosine nucleotide. Cov nucleotide no koom nrog hauv kev tsim lariat.
Daim duab 01: Cis thiab Trans Splicing
Cov spliceosomes loj yog U1, U2, U4, U5 thiab U6. Ntawm lawv, U1 thiab U2 tseem ceeb heev. Hauv cis splicing, U1 khi rau 5 'splice site, thiab U2 khi rau ceg taw tes ze ntawm 3' splice site. U5 / U4 / U6 khi exons ntawm qhov chaw 5, nrog U6 khi rau U2. Tom qab ntawd, U1 raug tso tawm. U5 hloov ntawm exon mus rau intron, thiab U6 khi ntawm 5 'splice site. Tsis tas li ntawd, U4 kuj raug tso tawm. U6 / U2 catalyzes transesterification, ua rau 5' kawg ntawm intron ligate rau A nucleotide ntawm intron. Qhov no ua rau lariat tsim. Hauv kev tsim cov lariat, U5 khi exon ntawm 3 'splice site, thiab 5' site yog cleaved. Nyob rau theem kawg ntawm kev sib txuas, U2 / U5 / U6 tseem khi rau lub lariat, thiab 3 'qhov chaw yog cleaved. Ntxiv rau qhov ntawd, cov exons yog ligated siv ATP hydrolysis nyob rau theem no.
Dab tsi yog Trans Splicing?
Trans splicing yog ib qho kev sib txuas lus uas tshem tawm cov intros lossis outrons thiab koom nrog cov exons uas tsis nyob hauv tib RNA cov ntawv sau tseg. Hauv trans-splice, tsis muaj 5 'splice site ntawm pre mRNA molecule rau U1 protein los khi. Hloov chaw, capped splice thawj coj (SL) RNA yog trans-spliced rau ib theem zuj zus nyob rau hauv lub outron.
Daim duab 02: Trans Splicing
Outron yog thaj tsam ntawm pre mRNA nruab nrab ntawm 5 'cap thiab trans splice site. Txawm li cas los xij, U2 protein khi rau 3 'splice site feem ntau. Tom qab tshem tawm outron, tus thawj coj splice (SL) exon yog spliced rau thawj exon ntawm pre mRNA. Tsis tas li ntawd, trans-splicing yog ib qho txheej txheem uas tau pom nyob rau hauv qee yam kab mob xws li protists ntawm Kinetoplastae chav kawm los qhia cov noob.
Dab tsi yog qhov zoo sib xws ntawm Cis thiab Trans Splicing?
- Cis thiab trans splicing yog ob hom RNA splicing mechanisms.
- Nyob rau hauv ob qho tib si mechanisms, introns raug tshem tawm.
- Tsis tas li, hauv ob qho tib si, exons tau koom ua ke los tsim mRNA paub tab.
- Ob lub tshuab muaj nyob hauv eukaryotes.
- Cov txheej txheem no tsis muaj nyob hauv prokaryotes.
Qhov txawv ntawm Cis thiab Trans Splicing yog dab tsi?
Cis splicing yog ib qho intramolecular mechanism uas tshem tawm cov intros thiab koom nrog cov exons uas nyob rau hauv tib RNA cov ntaub ntawv sau tseg, thaum trans-spling yog ib qho kev sib txuas lus uas tshem tawm introns lossis outrons thiab koom nrog cov exons uas tsis nyob hauv tib RNA. cov ntawv sau tseg. Yog li, qhov no yog qhov sib txawv tseem ceeb ntawm cis thiab trans splicing. Tsis tas li ntawd, hauv cis splicing, introns raug tshem tawm los ua mRNA paub tab. Ntawm qhov tod tes, hauv trans splicing introns lossis outrons raug tshem tawm los ua mRNA paub tab.
Cov infographic hauv qab no teev qhov sib txawv ntawm cis thiab trans splicing hauv daim ntawv tabular rau ib sab ntawm kev sib piv.
Summary – Cis vs Trans Splicing
RNA splicing yog ib daim ntawv ntawm RNA ua ntej cov txheej txheem protein synthesis. Cis thiab trans splicing yog ob hom RNA splicing mechanisms uas muaj nyob rau hauv eukaryotes. Cis splicing yog ib qho intramolecular mechanism uas tshem tawm introns thiab koom nrog cov exons uas nyob rau hauv tib RNA cov ntaub ntawv sau tseg, thaum trans-splicing yog ib qho kev sib txuas lus uas tshem tawm introns lossis outrons thiab koom nrog cov exons uas tsis nyob hauv tib RNA cov ntawv sau tseg. Yog li, qhov no xaus qhov kev sib tham ntawm qhov sib txawv ntawm cis thiab trans splicing.
