Transcription of eukaryotic genes can be repressed in various ways. These include the four mechanisms

1. Competition	a-Repression is caused by recruiting histone modifiers that alter nucleosomes in ways that inhibit transcript
2. Inhibition	b-A repressor binds to a site on DNA beside an activator and interacts with that activator, occluding its activating region
3. Direct repression	c-By binding to a site on DNA that overlaps the binding site of an activator, a repressor can inhibit binding of the activator to a gene and thus block activation of that gene.
4. Indirect repression	d-A repressor binds to a site upstream of a gene and, by interacting with the transcriptional machinery at the promoter in some specific way, inhibits transcription initiation.

#Question id: 1403

#Unit 4. Cell Communication and Cell Signaling

Tumor-suppressor genes encode proteins with which of the following functions?

a. growth-promoting               b. growth-arresting                  c. pro-apoptotic

d. anti-apoptotic                      e. DNA repair

#Question id: 1404

#Unit 4. Cell Communication and Cell Signaling

Which of the following are transcription factors?

#Question id: 1405

#Unit 4. Cell Communication and Cell Signaling

A gain-of-function mutation in which of the following would have the same effect as a gain-of-function mutation in Ras?

#Question id: 1406

#Unit 4. Cell Communication and Cell Signaling

Which of the following is a consequence of p53 stabilization?

a. stabilization of Cdc25A      b. activation of ATM                c. blocked apoptosis

d. transcription of p21                        e. DNA repair

#Question id: 1407

#Unit 4. Cell Communication and Cell Signaling

Which of the following is pro-apoptotic?

a. Bax              b. Bcl-2                       c. p53              d. protein kinase B      e. PTEN

#Question id: 1408

#Unit 4. Cell Communication and Cell Signaling

Human papilloma virus encodes proteins that inhibit the function of

a. Bcl-2.           b. Myc.                        c. p53.             d. PDGF receptor.      e. Rb.