46.   Chromatin condensation is facilitated by SMC proteins which act to:

A.    Disassemble histone proteins

B.    Act as a scaffold to support highly condensed DNA

C.    Interfere with negatively charged phosphate backbones

D.    Daisy-chain nucleosomes

E.     Block the formation of the 30nm fibre

47.   SWI/SNF complexes contain up to 1 1 different subunits, one of which contains a motif important for acetylation recognition called a:

A.    Bromodomain

B.    Chromodomain

C. Ligand binding domain

D.   RNA polymerase activity.

E.    Helicase

48.   The vitamin D receptor (VDR) binds to and activates the Cyp24 promoter. You obtain a plasmid that contains the Cyp24 promoter upstream of the lacZ reporter gene. From this you create two new plasmids that each contain a different mutation in the Cyp24 promoter: mutation A and mutation B, each of which may be VDR binding elements. When you transfect each plasmid into cells, you observe that the plasmid containing mutation A results in 2-fold less ßgalactosidase activity compared to the unmutated plasmid. You also observe that the plasmid containing mutation B results in equivalent ß-galactosidase activity compared to the unmutated plasmid. What can you conclude from this experiment?

A.               Mutation A completely abolishes VDR binding.

B.                Both mutation A and B completely abolish VDR binding.

C. Mutation B is in a VDR binding site, but mutation A is not.

D. Mutation A is in a VDR binding site, but mutation B is not.

E.  VDR binding to the Cyp24 promoter actually suppresses promoter activity