Exam 3 Retrovirology Flashcards

1
Q

Central dogma

A

DNA to RNA to protein

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2
Q

Retroviruses use a _____ template, which means they violate _____

A

RNA; Central dogma

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3
Q

Retroviruses make ____ from an RNA template

A

RNA to DNA to RNA to protein

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4
Q

Retroviruses use _____ to get from RNA to DNA

A

Reverse transcription

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5
Q

Retroviruses - characterization

A
  • group of enveloped RNA (positive strand) viruses
  • unique mode of viral replication
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6
Q

Retroviruses use what enzyme for viral replication?

A
  • RNA-dependent DNA polymerase
  • Reverse transcriptase
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7
Q

Reverse transcriptase is abbreviated as:

A

RT or RTase

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8
Q

Retroviruses enter the cell as a ____ RNA accompanied by ____

A

Positive strand RNA; RNA enzyme (RT)

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9
Q

After DNA is made from RNA template, what happens?

A

It is integrated into host DNA (provirus)

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10
Q

Provirus is located in the:

A

Nucleus

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11
Q

Two classifications of retroviruses (families)

A
  • Oncovirinae (onco-rna-viruses)
  • Lentivirinae (Lentiviruses)
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12
Q

What virus is a part of the oncovirinae?

A

HTLV

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13
Q

What virus is a part of the lentivirinae?

A

HIV

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14
Q

HTLV stands for:

A

Human T-lymphotrophic virus

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15
Q

HIV stands for:

A

Human immunodeficiency virus

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16
Q

What is the morphology of the HTLV capsid?

A

C-type (central, spherical)

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17
Q

What is the morphology of the HIV capsid?

A

D-type (central, cone-shaped cylindrical)

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18
Q

Characteristics of retroviral infective virion

A
  • Enveloped nucleocapsid
  • Two copies of positive strand ssRNA
  • Reverse transcriptase (RTase)
  • Integrase
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19
Q

The retroviral envelope is acquired from _____ and contains _____

A

Host plasma membrane; viral proteins

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20
Q

The retroviral nucleocapsid contains:

A
  • Two identical copies of positive strand (+) ssRNA virus
  • Multiple copies of RTase
  • Integrase
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21
Q

What glycoprotein is found in HTLV envelope?

A

gp62

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22
Q

What glycoprotein is found in HIV envelope?

A

gp160

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23
Q

Components of gp62

A

gp46 and gp21

24
Q

In the gp62 glycoprotein of HTLV, ____ is for docking and ____ is for fusion

A

gp46; gp21

25
Q

In the gp160 glycoprotein of HIV, ____ is for docking and ____ is for fusion

A

gp120; gp41

26
Q

The docking protein on the viral envelope determines ____, and the smaller protein promotes _____

A

Tropism; fusion

27
Q

What are the three major retrovirus genes?

A
  • GAG
  • POL
  • ENV
28
Q

What does the GAG retrovirus gene code for?

A

Capsid, matrix, and binding proteins

29
Q

What does the POL retrovirus gene code for?

A

Polymerases, proteases, integrases

30
Q

What does the ENV retrovirus gene code for?

A

Envelope glycoproteins (ex. gp46)

31
Q

The retrovirus lifecycle includes unique steps such as:

A

Reverse transcription and integration

32
Q

In HIV, what is the most distal, external portion on the envelope?

A

gp120

33
Q

gp120 (HIV) binds ____ on the host

A

CD4 (primary receptor)

34
Q

HIV uses co-receptors such as _____ found on the ____ to get into the T cell

A

CCR5 and CXCR4; host

35
Q

HTLV gp46 binds ____ along with ____

A

CD4; co-receptors

36
Q

What are the functions of RTase?

A
  • Reverse transcription from RNA into DNA (forms RNA-DNA hybrid)
  • Ribonuclease H function (degrades RNA-DNA hybrid)
  • DNA polymerase function (synthesizes + DNA)
37
Q

Reverse transcriptase error rate

A

1 error per 2,000 bases (highly error prone)

38
Q

What is a provirus?

A

Integrated viral genome in host DNA (formed after integrase activity)

39
Q

Retrovirus incubation periods

A

May be long (months or years for HIV and HTLV)

40
Q

Provirus may remain in ____ until ____ activates cells which may activate the virus

A

Latency; immune response

41
Q

Transcription factors in immune response

A

NFkB; also bind LTR (long terminal repeats)

activate HIV or HTLV

42
Q

Retroviruses are released by ____ and may form ____

A

Budding; syncytia

43
Q

_____ are fused, multi-nucleated cells

A

Syncytia

44
Q

tax is a transcription factor found in ____

A

HTLV

45
Q

tat is a transcription factor found in ____

A

HIV

46
Q

Tax transcription factor is involved with _____ production

A

IL-2 and IL-2R (autocrine and paracrine)

47
Q

Tax promotes:

A

Viral replication

48
Q

There are several types of HTLV presentations, such as:

A
  • HTLV-1: ATL
  • HTLV-2: Atypical hairy cell (cutaneous) leukemia
49
Q

What is ATL?

A

Adult acute T-cell lymphocytic leukemia

50
Q

There are several types of HTLV-related oral symptoms, such as:

A
  • Xerostomia
  • Fissured tongue
  • Loss of tongue papilla
51
Q

HTLV-1 radiographic findings

A
  • Unusual presentation of bone invasion and osteolysis
  • Raindrop skull
52
Q

Raindrop skull can be caused by:

A
  • Myeloma
  • HTLV
53
Q

_____ is the most common form of cutaneous T-cell lymphoma

A

HTLV-2 hairy cell leukemia

54
Q

For HTLV diagnosis and treatment, ____ is indicated to look for _____ or _____

A

Serology; leukemia or lymphoma

55
Q

HTLV involves proliferation of ____

A

T cells