Presentation Transkripsi Fix

8/3/2019 Presentation Transkripsi Fix

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Adelya Desi K.

Novia Nur R.

Rista Anggriani

TRANSCRIPTION IN

EUCARYOTES

Biology Cell & Molecular


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Central Dogma

duplication of DNA using DNAas the template

synthesis of RNA using DNA

as the template

synthesis of proteins using RNA

as the template


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Procaryotes VS Eucaryotes

Procaryotes

Eucaryotes

Unlike procaryotes, for the RNA to

be translated, it must move out of

the nucleus into the cytoplasm.


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General Transcription

InitiationThe RNA polymerase

attach to DNA promoter,

begin synthesis the

mRNA

ElongationElongated the mRNA by

RNA polymerase

TerminationRelease the RNA

polymerase from DNA

template, and the

product is mRNA

RNA polymerase

mRNA

DNA template


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Transcription in Eucaryotes

o In eucaryotes genes, there are only

monocistronic [one transcription product only

coding one expression]

oTranscription in eucaryotes occur within thenucleus under the direction of3 separate

forms of RNA polymerase.

RNA

Form

Product Location Gene

ClassI rRNA Nucleous I

II mRNA Nucleoplasm II

III 5S rRNA & tRNA Nucleoplasm III


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Transcription in Eucaryotes

In the class I gene, the product is rRNAthis gene only transcript, and not to be translate,

because the product expression needed is the

rRNA.

in the class II gene, its include all genes which

coding many kinds of protein. The product of this

transcription is mRNA. the promoter in this gene

included by 4 element, there are initiator

sequence, downstream, TATA box, and upstream.

In the class III gene, its coding the tRNA, 5S

rRNA, and some little RNA molecules in nucleus.


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Transcription in Class II Gene

phase : initiation, elongation, terminationEnzyme : RNA polymerase II

Product : mRNA

Transcription begin from the Promoter sequence. The

difference of the eucaryotes and procaryotes is the

TATA box, which its included in promotor sequence.

TATA box is located in 25bp upstream (-25) from the

start point of transcription

TATA box has resposibility for fixing the site of

initiation of transcription, which is the place for RNA

polymerase attached.


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Promoter of RNA polymerase II


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When RNA polymerase attached into the

promoter (TATA box), its also need some

protein which its called Transcription

Factor (TF)

There are some type ofTF such as TFIIA,

TFIIB, TFIID, TFIIE, TFIIF, TFIIH,

TFIIJ


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3

3

5

5

-

25

+1

Transcribed gene sequencePromoter

TATADNA


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3

3

5

5

+1

DNA

TFIID


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3

3

5

5

+1

DNA

TFIIA,TFIIB


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3

3

5

5

+1

DNA

RNAPol II


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3

3

5

5

+1

DNA

TFIIF,E,H,J


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RNA

5

5

5

3

3


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Function of Human GTFs (General Transcription Factors)


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mRNA Processing

In eucaryotes, the product of transcription gene is

pre-mRNA. There are one more process to make

the pre-mRNA become mature mRNA, its called

mRNA Processing.

1. mRNA splicing

2. capping and

polyadenylation

3. rRNA and tRNAprocessing


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Splicing mRNA

Pre-mRNA in eucaryotes formed by exon(coding sequence) and intron (non-codingsequence).

Intron sequence are present in initial RNAtranscripts, but they are removed before the

mature mRNA is translated.

The removal of the sequence present inintron occurs as a result of an excision and

rejoining process of RNA reffered to as

splicing


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mRNA Splicing takes place within spliceosome


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mRNA Splicing

Removed the intron sequence

and splicing the exon


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5 Capping

1. Fosfatase2. Guanylyl transferase

(5-to-5 GMP)

3. Guanine

methyltransferase

Most eukaryotic mRNAs

have a 5 cap

Increases the stability of

mRNA


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3 Polyadenilation


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5 Capping & 3 Polyadenilation

Adding 7-methylguanosin(GTP + CH3) in 5 site to

prevent degradation by

endonuclease in 5 site

Adding 250 adenin in 3site to form poli-A tail to

prevent degradation by

endonuclease in 3 site


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Transcription in Class I Gene

Enzyme : RNA polymerase IProduct : rRNA (ribosomal RNA)

General architectur of gene promoter

Procaryotes (70 S) Eucaryotes (80 S)

Large subunit Small subunit Large subunit Small subunit

50S 30S 60S 40S

A comparisons between procaryotes and eucaryotes ribosom


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Transcription in Class III Gene

Enzyme : RNA polymerase III

Product : tRNA

RNA polymerase III

recognizesseveral different types of

promoters


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tRNA Processing

There are 74 95 RNA nucleotides together andmake a cloverleaf structure

5

A

C

C

3

Acceptor arm

dHU armOptional arm

TNC arm

Anticodon arm


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tRNA components

Acceptor arm: has CCA3 site, which

is the binding site with amini acid

Anticodon arm: has a function to

recognize and attached the match

codon in mRNA


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tRNA

Interpreter between

base sequence of

mRNA and amino

acid sequence ofprotein

45 different types

About 80 nucleotides

Long

Anticodon base pairs

with codon of mRNA


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THANK YOU.

Biology Cell & Molecular

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