To Study the Chromatin Remodeling Complex SWR1, a Researcher Has

Multiple Choice

To study the chromatin remodeling complex SWR1, a researcher has prepared arrays of nucleosomes on long DNA strands that have been immobilized on magnetic beads. These nucleosomes are then incubated with an excess of the H2AZ-H2B dimer (which contains the histone variant H2AZ) in the presence or absence of SWR1 with or without ATP. She then separates the bead-bound nucleosomes (bound fraction) from the rest of the mix (unbound fraction) using a magnet, elutes the bound fraction from the beads, and performs SDS-PAGE on the samples. This is followed by a Western blot using an antibody specific to the H2AZ protein used in this experiment. The results are shown below, with the presence (+) or absence (-) of ATP, SWR1, or the H2AZ-H2B dimer in each incubation reaction indicated at the top of the corresponding lane.
Which of the following statements is confirmed by the Western blot shown?

A) SWR1 deposits H2AZ histones into the nucleosome arrays.
B) SWR1 function is not ATP-dependent.
C) The antibody used in this experiment binds to the SWR1 complex.
D) All of the above.