BIOL 200 Lecture Notes - Lecture 47: Rna Interference, Invertebrate, Dicer
Document Summary
How can the transcription complex assemble on dna when it is all wound up? (cid:120) dna is not naked in cells (cid:120) It is associated with histone proteins (h1-h4) that bind it strongly and wind it up into higher-order structures called nucleosomes (cid:120) the nucleosomes are necessary to package the genomic dna into the nucleus in the form of chromosomes. The power of yeast genetics and biochemistry (cid:120) three genetic loci on chromosome iii genetically control the mating type of. This silencer works outside the context of mating and can even block expression of trna genes (rna pol iii) (cid:120) genetic experiments indicate that histones (h3 & h4) affect repression, while regions around telomeres behave similarly. Transcriptional repressors may act through histone deacetylation complexes (hdacs) (cid:120) positive charge of n-terminal histone tail interacts electrostatically with the dna phosphate groups (cid:120) transcriptional pre-initiation complex cannot form on.
