You have discovered a new species of plant. You isolate chromatin from the plant and examines it with the electron microscope and see characteristic beads on a string structure. After addition of a small amount of nuclease, which cleaves the string into individual beads that each contain 280 bp of DNA. With more digestion a 120-bp fragment of DNA remains attached to a core of histone protein. Analysis of the histone core reveals histones in the following proportions: H2A 33.3% H2B 33.3% H3 0% [no histone H3 found] H4 33.3% Based on these observations, what conclusions can you make about the probable structure of the nucleosome in the chromatin of this plant? Be specific in describing the nature of the nucleosome: which histones form the core (), how many of each are present () and size in bp of core-DNA that envelopes it ().

You are working in a lab studying Progeria. You design an expression vector containing a mutated form of the lamin gene that codes for a lamin protein that can no longer be phosphorylated. What do you predict would happen if you express this mutant form of lamin in a cell line? Lamin proteins would not be transported into the nucleus and would remain in the cytosol. Nuclear lamins will be unable to produce dimers, as the coiled-coil formation will be disrupted. Disassembly of the nuclear lamins will occur prematurely. Nuclear lamins will no longer disassemble properly during prometaphase. O Nuclear lamins will no longer assemble properly during telophase.

You are interested in studying a gene called pumper that is important for heart function. The pumper gene is only expressed (transcribed) in heart cells, and you think the reason for this may have to do with chromatin structure. To investigate this, you isolate chromatin from heart cells and skin cells, and perform a long digestion of both samples with DNAse I, a non-sequence specific enzyme that will cut the phosphodiester bonds linking adjacent nucleotides. You then remove all proteins and analyze the DNA by gel-electrophoresis. You are able to detect only the DNA fragments that contain the pumper gene. The bands at the top of lane 2 indicate very large DNA fragments that were not able to migrate very far in the gel. The numbers to the left indicate where in the gel DNA fragments of the indicated size would migrate. Based on this data, which of the following is likely to be TRUE regarding the pumper locus in heart cells? (select all that apply) hyper-acetylation of lysine on Histone…

Description about nucleosome what general type of interaction is(are) largely responsible for the protein-dna associations in a nuclosome? explain