Lecture 11 - Transformation

Question 1

“Transformation” refers to a change in cell growth properties leading to the ______ to form tumors.

Answer 1

Potential

Question 2

Some of the advantages of infecting a single cell in culture include being able to observe ______ events at the cellular and sub-cellular level. However, recognizing transformation in a single cell doesn’t always correspond to _____ formation in animals.

Answer 2

Regulatory

Tumor

Question 3

_____ formation is a quantitative assay whereby immortalized cells are culture to form a monolayer. Then, a cell is infected with the virus of interest and forms (or doesn’t form) _____. The number of _____ is a measure of the transforming potential of the virus.

Answer 3

Focus

Foci

Foci

Question 4

Transformed cells have a ______ requirement for growth factors and lose their dependence on _______ for growth (which is why they can grow in a soft agar medium.)

Answer 4

Decreased

Anchorage

Question 5

Rous Sarcoma Virus (RSV) is actually an evolved form of _____. RSV “picked up” a human _____ gene.

Answer 5

ALV

Src

Question 6

The reason v-Src is oncogenic is because it is _____ and lacks the C-terminal _____-inhibitory domain. In the inactive conformation, the normal Src protein contains a phosphorylated _____ (amino acid) in the C-terminal.

Answer 6

Truncated

Auto-inhibitory

Tyrosine

Question 7

Some distinguishing characteristics of Acute transforming retroviruses are that they are almost all _______ defective (non-productive infection.) Many target cells are transformed, so tumors are ______ (as opposed to monoclonal which is characteristic of Chronic transformation.)

Answer 7

Replication

Polyclonal

Question 8

Acute transformation can be either Qualitative or Quantitative. ______ is when a structural change or mutation in a gene occurs such that the protein product becomes constitutively active. ______ is when expression of the acquired gene is under control of the viral _____ (promoter.)

Answer 8

Qualitative

Quantitative

LTR

Question 9

For any virus to cause cancer, it must meet both of the following requirements:

1. The virus persists in ____ cells as ____.
2. The virus maintains the expression of a viral or host _____.

Answer 9

Tumor

DNA

Onconge

Question 10

DNA tumor viruses cause cancer in ____-_______ infections.

Answer 10

Non-Productive

Question 11

Large DNA viruses cause cancer during ______, when their genome exists as an _____.

Answer 11

Latency

Episome

Question 12

EBV (aka HHV__) infects ___ lymphocytes and epithelial cells of pharyngeal mucosa.

Answer 12

HHV4

B-lymphocytes

Question 13

During latency, EBV replication genes “shut down.” Instead, _____ gene are active and promote cell survival.

Answer 13

Latency genes

Question 14

B-________ disease, _______ carcinoma, and T and ___ cell lymphomas are ALWAYS associated with EBV infection.

Answer 14

B-lymphoproliferative disease

Nasopharyngeal carcinoma

T and NK cell lymphomas

Question 15

Three genes are essential for EBV infection to give rise to cancer:

1. _____-2 which is a transcriptional activator of the promoter of the oncogene or can directly activate c-___.
2. ____-1, which is the oncogene that constitutively activates _____-kappaB.
3. _____-1, which is required for replicating the latent episomal genome and tethering it to host chromosome.

Answer 15

EBNA-2

c-Myc

LMP-1

NF-kappaB

EBNA-1

Question 16

LMP-1 can also mimic the B-cell CD-____ receptor, which normally activates B-cells upon interaction with T-cells. The difference is the LMP-1 does NOT need a ligand to initiate the signalling cascade.

Answer 16

CD-40

Question 17

Kaposi’s sarcoma-associated Herpesvirus (KSHV/HHV8) causes _____ tumors, which is the leading neoplasm in AIDS patients. One of the distinguishing characteristics of KSHV is that is expresses acquired oncogenes during ______ infection (lytic cycle, not latent infection.) The acquired oncogenes are associated with delayed ____ genes of the virus.

Answer 17

Endothelial

Productive

Early

Question 18

Viral transforming proteins can be any one of the following:

1. Growth Factors
2. Growth Factor _____
3. Intracellular transducers
4. Intracellular receptors
5. Transcription factors
6. DNA-repair proteins
7. Cell-cycle control proteins
8. Anti-_____ proteins

Answer 18

Receptors

Anti-Apoptotic proteins