Ch.8 DNA Template

Question 1

What does a DNA virus need to synthesize proteins?

Answer 1

Viral mRNA (via DNA dep. RNA Pol.)

Question 2

What is a hallmark of DNA viruses?

Answer 2

expression in a strictly defined sequence

Question 3

What is made during the initial period of infection?

Answer 3

Enzymes and regulatory proteins

Question 4

What is made after viral DNA synthesis?

Answer 4

Structural proteins

Question 5

In eukaryotes, what does RNA Pol I make?

Answer 5

Ribosomal RNA

Question 6

In eukaryotes, what does RNA Pol II make?

Answer 6

mRNA species and precursors of small regulatory RNA

Question 7

In eukaryotes, what does RNA Pol III make?

Answer 7

tRNA

Question 8

When are dsDNA virus ready to be transcribed?

Answer 8

Once they enter the nucleus.

Question 9

Initiation of transcription by Pol II is mediated by a

Answer 9

promoter region

Question 10

What is present in the transcriptional control region?

Answer 10

The promoter along with a set of DNA sequences controlling transcription.

Question 11

What are core promoters? What is their hallmark?

Answer 11

Sequences necessary for recognition and assembly of pre-initiation complexes; TA rich sequences 20-35bp upstream of the initiation site (TATA box)

Question 12

What recognizes the TATA box?

Answer 12

TATA-box binding protein

Question 13

What is a holozyme?

Answer 13

RNA Pol II in complex with proteins poised to initiate transcription

Question 14

What are the three steps of transcription via Pol II

Answer 14

promoter recognition, unwinding of DNA, movement of transcriptional complex

Question 15

Does a regulatory sequence have to be local?

Answer 15

NO, local and distant sequences can control transcription

Question 16

What recognizes local regulatory sequences?

Answer 16

Sequence specific DNA binding proteins (first seen in SV40)

Question 17

What are enhancers? How far can they be from the start site?

Answer 17

DNA elements that can stimulate transcription. THey can be up to 10000 bp away

Question 18

What are the common properties of transcription regulating proteins?

Answer 18

They have a DNA binding domain; They dimerize to bind to DNA through dimerization domain; Activation domain function as an independent unit; Coactivator binding sites (modulate transcription by modification of transcription regulating proteins)

Question 19

what are the two patterns of viral regulation of RNA pol II?

Answer 19

1-positive autoregulatory loop: rate of transcription is stimulated but doesn’t change what is being produced;
2-transcriptional cascade: Viral transcriptional units are activated in a fixed sequence.

Question 20

What are the 3 categories of DNA viral genes?

Answer 20

immediate early; early; late. IE and E are transcribed to ensure genome replication occurs before L proteins are produced. L are generally structural proteins

Question 21

The Adenovirus genome contains____ RNA pol II transcriptional units which encode more than ___ proteins

Answer 21

8; 40

Question 22

In adenovirus what is required for progression of the infectious cycle? why is it required?

Answer 22

Functional E1A; it is necessary for transcription of early genes, E2, which is necessary for viralDNA syn. and entry into late phase

Question 23

Unlike adenovirus, HSV1 imporants structural protein _____ during infection. What is it necessary for? How does it work?

Answer 23

VP16; efficient transcription of IE genes; it lacks a DNA binding site but it has an acidic activation domain which stimulates unwinding of DNA by another protein.

Question 24

Epstein-Barr virus expresses ____ after infection. what regulator interrupts latency? What represses this protein?

Answer 24

only a few genes required for replication (latent phase) ; Zta (a sequence specific binding protein); binding with cellular proteins p53 and p65

Question 25

Drugs or mutations that inhibit replication also inhibit _____ ___ _______ ________

Answer 25

synthesis of late genes

Question 26

What is the latency/lytic state regulated by?

Answer 26

transcriptional programs