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(Solved): label answers by question numberthe second picture is a close up of the diagram in the first picture ...
label answers by question number
the second picture is a close up of the diagram in the first picture
The three HP1 reader proteins in humans - HP , and HP1 share a highly conserved domain that directs their localization to chromatin. To determine whether these proteins could bind to the histone -terminus, you have covalently attached to separate beads various versions of the -terminal peptide - unmodified (unmod), Lys9trimethylated (K9-M), and Ser10-phosphorylated (S10-P)-along with an unmodified tail from histone H4 (see the figure Part A). You incubate the beads with various input (I) proteins, wash away unbound (U) proteins, and then elute bound (B) proteins for assay using protein-specific antibodies (Part B). The assay includes results from several control proteins, including Pax5, which is a transcription regulator, polycomb protein , which is known to bind to histones, and Suv39h1, a histone methyl transferase. Q.I Based on these results, which of the tested proteins binds to the unmodified tails of histones H3 and H4? Explain Q.2 Which proteins are binding to of ? Q.3 Which proteins will bind to S10-P of H3
(Part B adapted from M. Lachner et al., Nature 410:116-120, 2001. With permission from Macmillan Pablishers Lid.)
Expert Answer
Question 1: Based on these results, which of the tested proteins binds to the unmodified tails of histones H3and H4? Explain. Solution: The findings of the experiment employing various input (I) proteins are displayed in three panels. The proteins put to the assay include Pax5, Pc1, Suv39h1, HP1?, HP1?, and HP1?.There are three lanes with the letters unbound (U), elute bound(B), and input(I) in each panel. The proteins that did not adhere to the beads and were washed away are represented by the "U" lane. The proteins that bonded to the beads and were eluted for further analysis are represented by the "B" lane. The input proteins used in the test are represented by the "I" lane.We need to examine the "B" lanes for the beads containing the unaltered H3 and H4 tails in order to identify the proteins that bind to them. In the "B" lanes of the beads with unchanged H3 and H4 tails, it seems from the picture that HP1?, HP1?, and HP1? are present. This shows that the unaltered tails of histones H3 and H4 can bind to all three HP1 reader proteins.In contrast, the "B" lanes of the beads with unaltered H3 and H4 tails do not contain Pax5, Pcl, or Suv39h1. Pax5, Pc1, and Suv39h1 do not bind to the unaltered tails of histones H3 and H4, according to the presented data.