The document discusses transcription and the central dogma of molecular biology. It states that genetic information flows from DNA to RNA to protein. This flow was described by Crick and is known as the central dogma. The document then discusses the classes of genes transcribed by eukaryotic RNA polymerase, the basic elements of transcription in eukaryotes including transcriptional factors, and provides an outline of eukaryotic transcription. It describes the first step of eukaryotic transcription as the formation of the pre-initiation complex and discusses the roles of various transcription factors in initiating transcription.

1. Transcription_
-Eukaryotes
GP-501 ; Dated: 22-10-2013
Asif B Shikari

3. ProteinRNADNA
Genetic information from DNA is transcribed to RNA and that
information from RNA is translated to polypeptide chain. This
concept of flow of biological information from DNA to RNA and
then to protein was given by Crick and is known as “Central
Dogma”. This central Dogma holds true for those organisms in
which DNA is genetic material.
TranslationTranscription
Central dogma
Self replication

5. Classes of genes transcribed by
eukarytoic RNA polymerase

6. Basic elements in Transcription

7. Classes of Transcriptional Factors

8. Outline of
Eukarytoic transcription

9. First Step in eukarytoic transcription
Pre-initiation complex

10.  TBP uses
extensive β-
sheet to
recognize the
minor groove of
TATA element.
 A:T base pairs
are favoured
because they
are more readily
distorted to
allow the initial
opening of the
minor groove.
 Also interactions
between P in
backbone and
basic residues in
β-sheet stabilize
association.
 TBP-TATA
binding means
specificity
Out of 10 TAFs, two bind at Inr element and
Downstream Promoter element

12.  TFIIB interacts with TBP and also with DNA at BRE
 Start site selection: [TFIIB mutants result in shift of transcription start
site]
 Results in Uni-directional transcription
 Pol II + TFIID +TFIIB form minimal initiation complex
 Functions in TFIIF recruitment

17. Tight Binding

19. TFIID RNAP
Elongation Phase Starts

20. Phosphorylation of the
polymerase could be
the trigger that allows
the polymerase to shift
from initiation
to elongation mode.

21.  Kinase P-TEFb is recruited to Polymerase by Transcriptional
activators
 Once bound, this enzyme phosphorylates Ser at Position 2 of
CTD repeats.
 P-TEFb phosphorylates hSTP5 protein and activates it. hSTP5
after activation leads to elongation.
 P-TEFb phosphorylates TAT-SF1 elongation factor.
 TFIIS is another factor which is recruited and stimulates
elongation and proof reading.
 Simultaneously, at the time of elongation, the enzymes for 5’
capping and polyadenylation are recruited at the
corresponding sites.
Elongation Phase continues

22. Prokaryotes Eukaryotes
A single RNA polymerase;
RNA Pol
Multiple RNA Polymerases;
Pol I, Pol II, Pol III
RNA polymerase binds
directly to Promoter
sequences
First GTFs bind to Promoter
& then binds Pol II (Pre-
initiation complex)
Sigma as specificity factor GTFs as specificity factors
Polycistronic message Transcription of single gene
Translation and
transcription is coupled
Transcription (Nucleus) and
Translation (Cytosol) are
independent
No definite phase of its
occurence
Occurs in G1 and G2 phase
of cell cycle
Comparing both

23. Prokaryotes Eukaryotes
RNAs are released and
processed in cytoplasm
RNAs processed in nucleus
Initiation doesnt need any
initiation factors
Initiation requires TFs
RNA Pol is complex of 5
polypeptides
RNA Pol is complex of 10-15
polypeptides
Little or no processing of
RNA
Capping, Splicing &
Polyadenylation takes place

24. Thankyou
all