EUKARYOTIC TRANSCRIPTION ENZYMES

Question 1

RNA Polymerase I

Answer 1

Function: transcribes RNA genes

Question 2

RNA Polymerase II

Answer 2

Function: mRNA (protein-coding genes), snRNAs, miRNAs
At promoter region until CTD is phosphorylated by TFIIH
Conformational change & moves away from promoter & elongates
Transcription factors released from DNA

Question 3

RNA Polymerase III

Answer 3

Function: tRNA genes & some snRNAs

Question 4

Cis Elements

Answer 4

Function: CG Box: -70 to -200
CAAT Box: -60 to -100
BRE Box: -35
TATA Box: -25 to -30
IN (Initiator Element): +1
DPE (Downstream Promoter Element): +25

Question 5

Trans Element

Answer 5

Function: General transcription factors

Question 6

TFIID

Answer 6

Function: contains TBP (TATA binding protein)

Recognizes TATA box sequence of promoter

Question 7

TFIIA

Answer 7

Function: Facilitates TBP binding to TATA box - stabilizes attachement

Question 8

TFIIB

Answer 8

Function: Recognizes initiation site BRE

Question 9

TFIIE

Answer 9

Function: Will associate with growing assembly of factors and attracts TFIIH

Question 10

TFIIF

Answer 10

Function: Stabilizes RNA polymerase by interacting with TBP & TFIIB

Question 11

TFIIH

Answer 11

Function: Helicase activity & Protein kinase activity to phosphorylated CTD

Question 12

CTD

Answer 12

Function: C-Terminal Domain of RNA Polymerase

Question 13

Eukaryotic Transcription

Answer 13

RNA Polymerase synthesizes RNA in 5’-3’ direction along 3’-5’ template DNA
No primer needed for RNA synthesis
Ribonucleoside triphosphates = building blocks for RNA polymerization
Template strand = anti-sense strand
Non-template strand = sense strand

Question 14

Eukaryotic Termination

Answer 14

Poly Adenylation (3’ tail)
At end of transcription, mRNA is cleaved by “cleavage factors” and it separates the mRNA from RNA/DNA hybrid. Poly A tail then added to 3’-end of released transcript