Eukaryotic transcription is carried out in the nucleus of the cell and proceeds in three sequential stages: initiation, elongation, and termination. Eukaryotes require transcription factors to first bind to the promoter region and then help recruit the appropriate polymerase.

1. TRANSCRIPTION IN EUKARYOTES
Dr.Rachana Choudhary
(HOD , Microbiology)
SHRI SHANKARACHARYA MAHAVIDYALAYA
JUNWANI, BHILAI

2. CONTENTS
• INTRODUCTION
• Definition
• history
• Enzymes involved in transcription
• Transcriptional Factor
• MACHANISM OF TRANSCRIPTION IN EUKARYOTES:
- INITIATION
- ELONGATION
- TERMINATION
• DIFFERENT BETWEEN PROKARYOTIC & EUKARYOTIC TRANSCRIPTION
• Significance
• reference
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3. INTRODUCTION
Transcription, or RNA Synthesis, is the process of
creating RNA, copy of a sequence of DNA.
 Both RNA and DNA are nucleic acids, which
use base pairs of nucleotides as a complementary
language that can be converted from DNA to RNA
in the presence of the correct enzymes.
During transcription, a DNA sequence is read
by RNA polymerase, which produces a
complementary, RNA strand.
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4. definition
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Transcription is a process in which a DNA strand provides
the information for the synthesis of RNA strand, in the
presence of DNA dependent RNA polymerase.

5. history
• Central dogma was proposed by Crick in 1958.
•The existence of mRNA was shown by Spiegel man and
coworkers in 1961.
•Activity of RNA polymerase was discovered by Werrin
1960.
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6. CHARACTERISTICS RNA POL I RNA POL II RNA POL III
Location Nucleolus Nucleoplasm Nucleoplasm
Target gene r RNA gene mRNA genes t RNA
55 r RNA
Promoters Upstream of
the start
point
Upstream of
the start point
Downstream of
the start point
Activity 5-70 % 20-40 % ~10%
Enzymesinvolvedintranscription

7. Eukaryotic RNAPs
In bacteria, all mRNA is made from the same RNA
polymerase. However, in eukaryotes, there are Three
Different RNA Polymerases.
1. RNA Polymerase I synthesizes rRNA.
2. RNA Polymerase II synthesizes all Protein Coding
Genes & mRNA.
3. RNA polymerase III synthesizes t RNAs and also
snRNAs (small nuclear RNAs) and small cellular
RNAs.
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8. Transcriptional factors
There are three types of transcriptional factors
(i) Basal
(ii) Upstream factor
(iii) Regulatory transcriptional factor
(i) BASAL: - They are required for initiation at all the promoters.
They join RNA Polymerase II to form a complex around Start
Point. There are different basal factors they are as follows:-TF
IIA ,TF IIB , TF IID , TF IIF , TF IIH, TF II I.
(ii) UPSTREAM FACTOR:- They increase the frequency of
initiation .e.g. SPI.
(iii) REGULATORY TRANSCRIPTION FACTOR :- They are
produced as activated at specific time as tissue. They control
transcription of the concerned gene.
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9. EUKARYOTIC TRANSCRIPTION PROCESS
The three step involved in transcription:-
1. Initiation
2. Elongation
3. Termination
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10. TRANSCRIPTION IN EUKARYOTES
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11. Initiation
In eukaryotes, the initiation of transcription, requires the
presence of a core promoter sequence in the DNA.
Promoters are regions of DNA which promote transcription
and are found around -10 to -35 base pairs upstream from
the start site of transcription. Core promoters are sequences
within the promoter which are essential for transcription
initiation. RNA polymerase is able to bind to core
promoters in the presence of various specific transcription
factors.

12. • The most common type of core promoter in eukaryotes is a short DNA
sequence known as a TATA box. The TATA box, as a core promoter, is
the binding site for a transcription factor known as TATA binding
protein (TBP), which is itself a subunit of another transcription factor,
called Transcription Factor II D (TFIID).
• One transcription factor, DNA helicase, has helicase activity and so is
involved in the separating of opposing strands of double-stranded DNA
to provide access to a single-stranded DNA template.
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13. ELONGATION
When the two strands get separated a
transcriptional bubble is formed and synthesis of
RNA begins from 5’-3’ end .As the transcription
bubble moves along the strands synthesis of mRNA
proceed.
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14. Eukaryotic RNA Termination
Transcription termination in eukaryotes is less understood
but involves cleavage of the new transcript followed by
template-independent addition of As at its new 3' end, in a
process called polyadenylation.
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16. MATURATION OF RNA
•In eukaryotes, the RNA is processed at both ends before
it is spliced.
•At the 5‘ end, a cap is added consisting of a modified
GTP (guanosine triphosphate). This occurs at the
beginning of transcription. The 5' cap is used as a
recognition signal for ribosomes to bind to the mRNA.
•At the 3' end, a poly(A) tail of 150 or more adenine
nucleotides is added. The tail plays a role in the stability
of the mRNA.
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17. DIFFERENT BETWEEN PROKARYOTIC & EUKARYOTIC
IN PROKARYOTES
•DNA dependent RNA
Polymerase-RNAPs.
•Promoter sequences-
TATpuATpu located -10 bp
of upstream.& TTGACA
Located -35 bp upstream.
•Post transcriptional changes
is none. Transcription and
translation takes place
simultaneously.
•Transcription factors not
required.
IN EUKARYOTES
• DNA dependent RNA
Polymerase-I,II,III.
• Promoter sequences-TATA
box Located-30bp
upstream.& CAAT box
Located -70 to -80bp
upstream.
• Co transcription and post
transcription change
present.
• Transcription factors
required.

18. •The single stranded intermediary RNA molecule
appropriately referred to as a mRNA is derived from DNA
by this process.
•Only one of the two strands of DNA gives rise to a
meaningful RNA product.
•One molecule of DNA will give rise to several molecules
of RNA , which are released from DNA templates.

19. Reference
GENES IX ;Benjamin Levin; jones & Bartlett
Publishers,2006.
B.D. Singh – Fundamental Genetic 4th Edition(2006)
 Dubey & Maheshwari – Microbiology
 S. Mahesh – Molecular Biology & Biophysics
 P.K. Gupta – Cell And Molecular Biology 2nd Edition
(2003)
 Lansing M. Prescott –Microbiology 6th Edition
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