Transcription Flashcards

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1
Q

In which direction is RNA transcribed? And the DNA strand read?

A

RNA transcribed 5’ to 3’

DNA read 3’ to 5’

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2
Q

The transcript created has the same sense as which strand? sense/non-sense

A

sense (non-template)

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3
Q

Sigma factor

A

~ locates the transcriptional start site by recognising the promoter
~ interacts with DNA via several domains
~ bacteria

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4
Q

Holoenzyme

A

a biochemically active compound formed by the combination of an enzyme with a coenzyme

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5
Q

RNA pol I

A

~ eukaryotes
~ rRNA
~ found in nuclelous

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6
Q

RNA pol II

A

~ eukaryotes
~ mRNA, snRNA, miRNA
~ found in nucleoplasm

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7
Q

RNA pol III

A

~ eukaryotes
~ rRNA, tRNA, snRNA
~ found in nucleoplasm

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8
Q

snRNA

A

small nuclear RNAs found in spliceosomes

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9
Q

miRNA

A

regulate gene expression

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10
Q

Core promoter elements

A

direct the binding of the transcription initiation complex

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11
Q

TBP

A

TATA-binding protein

~ when it binds to TATA box it promotes the binding of TFIIB to the BRE sequence

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12
Q

BRE

A

TFIIB recognition element

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13
Q

Which RNA pols is TBP important for?

A

I, II and III

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14
Q

Promoter clearance

A

displacement of the protein loop helps polymerase to break away from the promoter

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15
Q

Comepare the functions of DNA gyrase and DNA topoisomerase I in E.coli.

A

~ DNA gyrase removes positive supercoils ahead

~ DNA topoisomerase I removes negative supercoils behind

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16
Q

Histone chaperones

A

remove nucleosomes ahead of RNA polymerase and reassembles them behind it
e.g. FACT, Asf1, Spt6
~ EUKRYOTES

17
Q

RNA polymerase can stall because of…

A

~ a mis-inserted nucleotide

~ changes in supercoiling, the tension must be relieved

18
Q

Type I terminator

A

a.k.a. Rho-independant or Intrinsic terminators
~ no additional factors required for termination
~ in E.coli

19
Q

Type II terminators

A

a.k.a. Rho-dependent terminators
~ Rho factor is required for termination (requires ATP)
~ in E.coli

20
Q

Allosteric model of termination

A

RNA pol II continues to transcribe after the polyadenylation signal but the mRNA is cleaved at the poly(A) signal and the 3’ end of the mRNA is processed

21
Q

Torpedo model of termination

A

after cleavage at the poly(A) site, anything downstream of it is digested by Rat1 (5’ to 3’ endonuclease)

22
Q

Abortive initiation

A

the release of short RNAs by RNA pol after it fails to make full length RNA on its first attempt