Qhov sib txawv tseem ceeb ntawm snRNA thiab snoRNA yog tias snRNA koom nrog lwm txoj kev sib txuas ntawm pre-mRNA thaum snoRNA koom nrog kev hloov kho rRNA thiab tRNA, mRNA kho, thiab genome imprinting.
RNA me me yog cov polymeric RNA molecules uas muaj tsawg dua 200 nucleotides. Lawv feem ntau tsis yog coding. Lawv muaj nyob hauv cov tub txib RNAs los nqa cov teeb liab. Cov RNAs me me pib los ntawm zoo meej ob-stranded RNA, uas yog tsim los ntawm kev ua ntawm RNA-dependant RNA polymerase. Cov RNAs me me ua lub luag haujlwm tseem ceeb hauv kev sib txawv ntawm tes, kev loj hlob thiab kev loj hlob, apoptosis, metabolism, tsiv teb tsaws, thiab kev tiv thaiv. Yog li ntawd, RNAs me me yog qhov tseem ceeb thiab tseem ceeb ntawm kev tswj hwm kev loj hlob thiab lub cev. Me me nuclear RNA thiab me me nucleolar RNA yog ob chav kawm ntawm me RNA molecules.
snRNA yog dab tsi?
Me me nuclear RNA lossis snRNA yog ib chav kawm ntawm cov me me RNA molecules pom nyob rau hauv lub nucleus ntawm eukaryotic hlwb. Qhov nruab nrab ntev ntawm snRNA yog kwv yees li 150 nucleotides. RNA polymerase II los yog RNA polymerase III transcribe snRNA. Lub luag haujlwm tseem ceeb ntawm snRNA yog kev ua haujlwm ntawm pre-messenger RNA hauv lub nucleus. Lawv kuj pab tswj cov kev hloov pauv lossis RNA polymerase II thiab tswj cov telomeres.
Daim duab 01: Mechanism of Action of Small RNA
Muaj ob chav kawm ntawm snRNA raws li cov yam ntxwv ua ntu zus thiab cuam tshuam cov protein xws li RNA khi LSm protein. Ob chav kawm yog Sm-class snRNA thiab Lsm-class snRNA. Sm-class snRNA muaj cov ntsiab lus uridine siab ntawm U1, U2, U4, U4atac, U5, U7, U11, thiab U12. RNA polymerase II transcribes SM-class snRNA. Tom qab cov ntawv sau ua ntej snRNA, lawv feem ntau tau txais 7-methylguanosine 5 'cap nyob rau hauv lub nucleus. Tom qab ntawd lawv raug xa tawm mus rau cytoplasm los ntawm nuclear pores rau kev ua haujlwm ntxiv. Lsm-class snRNA muaj cov ntsiab lus uridine siab ntawm U6 thiab U6atac. RNA polymerase III transcribes Lsm-class snRNA, thiab nws tsis tawm hauv lub nucleus. Cov tib neeg snRNA feem ntau yog U1 spliceosomal RNA, U2 spliceosomal RNA, U4 spliceosomal RNA, U5 spliceosomal RNA, thiab U6 spliceosomal RNA.
snoRNA yog dab tsi?
Me me nucleolar RNA lossis snoRNA yog ib chav kawm ntawm RNA me me molecules uas qhia kev hloov tshuaj lom neeg hauv lwm RNA xws li ribosomal RNA, hloov RNA, thiab me me nuclear RNA. Txhua snoRNA molecule yog txuam nrog nyob ib ncig ntawm plaub core proteins nyob rau hauv RNA/protein complex thaum lub sij hawm hloov kho. Lub snoRNA muaj cov tshuaj tiv thaiv kab mob uas nyob ib puag ncig 10-20 nucleotides. Cov hauv paus no yog pub dawb rau cov kab ke nyob ib puag ncig cov nucleotides uas lub hom phiaj kev hloov kho hauv pre-RNA molecule.
Daim duab 02: Me Nucleolar RNA
Muaj ob chav kawm ntawm snoRNAs. Lawv yog C / D lub thawv snoRNA thiab H / ACA lub thawv snoRNA. C / D lub thawv snoRNA cuam tshuam nrog methylation, thiab H / ACA lub thawv snoRNA cuam tshuam nrog pseudo-uridylation. Txhua snoRNA molecule ua raws li kev qhia rau ib lossis ob qhov kev hloov kho hauv lub hom phiaj RNA. C / D lub thawv snoRNA muaj ob qhov kev txuag luv luv motifs C thiab D, nyob ze ntawm 5' thiab 3' kawg ntawm snoRNA, feem. Cov cheeb tsam luv luv uas muaj 5 nucleotides npaj cov dej ntws ntawm C lub thawv thiab nqes dej ntawm lub thawv D thiab tsim cov qauv qia-box. Qhov no coj C thiab D lub thawv motifs kom ze ze. Stem-box qauv yog qhov tseem ceeb rau qhov tseeb snoRNA synthesis thiab nucleolar localization. H / ACA lub thawv snoRNA muaj cov qauv thib ob uas muaj ob lub hairpins thiab ob thaj tsam ib leeg. Qhov no feem ntau hu ua hairpin-hinge-hairpin-tail qauv. H/ACA lub thawv snoRNA kuj muaj ob lub motifs H thiab ACA. Ob leeg nyob hauv ib cheeb tsam ib leeg. H lub thawv yog nyob rau hauv pob khawm, thiab ACA yog nyob rau hauv cheeb tsam tus Tsov tus tw. Peb nucleotides tsim 3' kawg ntawm qhov sib lawv liag.
Dab tsi zoo sib xws Ntawm snRNA thiab snoRNA?
- snRNA thiab snoRNA yog me RNAs.
- Ob leeg muaj nyob hauv cov hlwb eukaryotic.
- Ob leeg tsis yog-coding RNA molecules.
- Ntxiv mus, lawv koom nrog kev hloov kho RNA thaum lub sijhawm hloov pauv.
Qhov txawv ntawm snRNA thiab snoRNA yog dab tsi?
snRNA koom nrog lwm txoj kev sib txuas ntawm pre-mRNA thaum snoRNA feem ntau hloov kho RNA molecules. Yog li, qhov no yog qhov sib txawv tseem ceeb ntawm snRNA thiab snoRNA. Tsis tas li ntawd, snRNAs muaj txog 150 nucleotides ntev thiab feem ntau pom muaj txuas nrog ib pawg ntawm cov proteins thiab complexes hu ua me me nuclear ribonucleoproteins. snoRNAs muaj txog 60-170 nucleotides ntev thiab feem ntau pom nyob rau hauv cov nucleolus.
Ntxiv mus, snRNAs tau sau los ntawm RNA polymerase II lossis RNA polymerase III whereas, snoRNA tsuas yog sau los ntawm RNA polymerase II xwb.
Cov hauv qab no infographic nthuav tawm qhov sib txawv ntawm snRNA thiab snoRNA hauv daim ntawv tabular rau ib sab ntawm kev sib piv.
Summary – snRNA vs snoRNA
snRNA thiab snoRNA yog cov chav kawm ntawm RNA molecules me me. snRNA koom nrog lwm txoj kev sib txuas ntawm pre-mRNA thaum snoRNA feem ntau hloov pauv RNA molecules. Yog li, qhov no yog qhov sib txawv tseem ceeb ntawm snRNA thiab snoRNA. Me RNA yog polymeric RNA molecules uas muaj tsawg dua 200 nucleotides ntev thiab feem ntau tsis yog coding. snRNAs muaj nyob rau hauv lub nucleus ntawm eukaryotes. snoRNAs muaj nyob rau hauv archaea thiab eukaryotes. Kev hloov pauv ntawm snRNA tshwm sim los ntawm RNA polymerase II thiab II, thaum tsuas yog RNA polymerase II koom nrog hauv kev sau snoRNA. Yog li, qhov no qhia txog qhov sib txawv ntawm snRNA thiab snoRNA.
