Lecture 5 Flashcards

1
Q

Which viral genome is synthesized by RNA Pol II?

A

Hepatitis Delta Virus genome RNA (HDV)

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2
Q

Which viral genome is synthesized by RNA pol III?

A

Adenovirus Type II VA-RNAs, Epstein Barr Virus EBER RNAs

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3
Q

How many base pairs are core promoter?

A

20-35

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4
Q

How many base pairs are local regulatory sequences?

A

1x10^2 - 5x10^2

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5
Q

How many base pairs are distant regulatory sequences?

A

1x10^2 - 10^4

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6
Q

What are the distant regulatory sequences independent of?

A

Position and orientation

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7
Q

What are the core promoter elements?

A

Initiator sequence and TATA sequence

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8
Q

What are the distant regulatory elements?

A

Enhancers, silencers

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9
Q

What consist of the promoter?

A

Core promoter elements and local regulatory sequences

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10
Q

What consist of the transcriptional control region?

A

Core promoter + Local and distant regulatory sequences

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11
Q

A property of co-activators

A

They do not bind DNA but can modulate transcription

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12
Q

What is the origin of transcriptional components for poxvirus?

A

Viral

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13
Q

What is the origin of transcriptional components for simple retroviruses?

A

Host

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14
Q

What is the origin of transcriptional components for complex retroviruses, papillomaviruses, polyomaviruses, and parvoviruses?

A

Host + One viral protein that regulates transcription

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15
Q

What is the origin of transcriptional components for bacteriophage T3 and T7?

A

Host + One viral protein that transcribes late genes

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16
Q

What is the origin of transcriptional components for bacteriophage T4, adenoviruses, and herpesviruses?

A

Host + Several viral proteins that act sequentially to stimulate transcription of particular set of viral genes

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17
Q

What happens in a transcriptional cascade?

A

Transcriptional units are activated in a fixed sequence

18
Q

What do positive autoregulatory loops do?

A

Alter the rate of transcription initiation, viral proteins stimulate transcription

19
Q

What do negative autoregulatory loops do?

A

Repress gene expression

20
Q

What are some autoregulatory viral transcriptional activators?

A

HSV ICP4, SV40 T

21
Q

What are some viral transcriptional activators that bind DNA?

A

ICP4, T, E2, and EBNA

22
Q

What are some viral transcriptional activators that bind host proteins?

A

HSV VP16

23
Q

What are some viral transcriptional activators that liberate host TAs?

A

E1A, E7, T

24
Q

When is the capping enzyme added?

A

When the RNA pol II C terminal domain is phosphorylated (After incorporation of 20-30NT)

25
Q

What sequence does the poly(A) addition site have?

A

AAUAAA

25
Q

What is the sequence of the site next to the poly(A) addition site?

A

GU/U

26
Q

What protein binds to the poly(A) addition site?

A

Cpsf

27
Q

What protein binds to the GU/U site?

A

Cstf

28
Q

What proteins bind between Cpsf and Cstf?

A

CfI and cfII

29
Q

When does the cleavage of the mRNA occur?

A

After the addition of poly(A) polymerase alongside CfI and CfII

30
Q

What protein is at the 5’P end of Cstf following cleavage?

A

CfII

31
Q

What protein is at the 3’-OH end of Cpsf following cleavage?

A

Poly (A) polymerase + CfI

32
Q

What protein is responsible for slow polyadenylation?

A

Poly(A) polymerase

33
Q

What protein is responsible for rapid polyadenylation?

A

PabII

34
Q

What happens to GU/U sequence after cleavage and dissociation of Cstf protein?

A

Degradation

35
Q

When is ATP used in polyadenylation and cleavage?

A

During slow and rapid polyadenylation

36
Q

How many A’s are added in polyadenylation

A

~200

37
Q

How many transesterification reactions happen during splicing?

A

Two

38
Q

What are the two kinds of splicing?

A

Constitutive and alternative

39
Q

What are the methods of alternative splicing?

A
  1. Exon skipping
  2. Alternative 5’ splice site
  3. Alternative 3’ splice site
40
Q

What are the roles of alternative splicing?

A

It adds value as:
It creates new functional genes.
Coding information of a small DNA genome is expanded.
Regulates gene expression.