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Unformatted text preview: nuclear hormone receptors (NR). a) Direct binding of NR to phosphorylated CBP to mediate transcriptional activation. b) Ligand-bound NR recruitment of an activation complex containing HAT (Histone Acetyl Transferase). c) NR recruitment of a mediator complex for RNA polymerase at the gene promoter. d) NR recruitment of splicing-related coactivators at the gene promoter. e) NR recruitment of a repressor complex containing HDAC (histone deacetylase). 22) The following is true about techniques used to analyze chromatin structure/function. a) Restriction analysis refers to the use of DNA restriction enzymes to identify the regions of chromatin that are actively transcribed or repressed, based on histone binding. b) Gene bashing refers to the use of DNAse to degrade DNA that is transcriptionally active. c) The histone core of a nucleosome can be defined by isolating the nucleosome directly from chromatin by affinity chromatography. d) ChIP refers to the use of anti-transcription factor antibodies to identify specific DNA sequences that are bound by a transcription factor of interest after digestion of DNA with restriction enzymes. e) Electron microscopy illustrates the regions of chromatin that contain specific gene sequences. 23) The following is NOT true about nuclear hormone receptors. a) They have a DNA binding domain containing a "zinc-finger" that binds to specific DNA sequences. b) After ligand binding, steroid receptors may be translocated from the cytoplasm to the nucleus in a manner correlated with their association or disassociation with HSP90. c) Orphan receptors may be activated by phosphorylation instead of ligand binding, mediated by protein kinase signaling pathways. d) Steroid receptors can function as homo-dimers that bind to a pallindromic DNA sequence. e) Non-steroidal nuclear receptors that function as heterodimers with the retinoid X receptor (RXR) can be classified according to the number of "spacer" nucleotides that separate their DNA binding site sequences, located in tandem on a single DNA strand. 24) The following is true...
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- Fall '08