Marcu Lecture 1

Marcu Lecture 1 - Marcu Lecture 1 - What determines how...

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Marcu Lecture 1 - What determines how fast a reponse is? o What the gene needs determines how fast is responds o Eg. You have a DNA complex, where the DNA has no frills an it needs just one modification on a transcription factor; you turn that factor on, and transcription occurs in minutes o But if you have a gene embedded in nucleosomes, with no transcription factors, these genes are buried in heterochromatin o Heterochromatin- transcriptionally inactive chromatin o Euchromatin- transcriptionally active o Has to do with histone octamers o Eg. The DNA has an immunoglobulin gene in a fibroblast are in a heterochromatin; gene is dead silent; fibroblast has to figure out a way to differentiate to a different ell type in order to turn on the immunoglobulin gene; this would take days to convert the cell to a stem cell o Post translational modifications These modifications regulate protein-protein interactions Chromatin remodeling proteins Co-activators of transcription that don’t bind to DNA but need to have somebody already bound to DNA for them to get there Co-repressor proteins Slide 4, 5 - Pol II can transcribe mRNAs and also miRNAs - miRNAs that get processed that regulates translation and to some degree transcription - Transcription can be divided into 4 steps o Initiation- doesn’t mean that the polymerase has moved off the start site; it means that its made the first few phosphodiester bonds at the beginning of the mRNA transcript; you have control of this step o Clearance of the elongation complex- release from the start site; has a separate control from initiation phase; then the polymerase gets going o Elongation - There are regulatory sequences downstream that affect the rate of its movement o Termination- specific termination sites in DNA that allow the pol to fall off - Processing- mRNA maturation (this is not transcription and is part of translational control) o Poly A adding o Splicing o All of these are post-transcriptional control - We now know mechanistically that poly A addition and splicing are linked to transcription; there is a linkage of common regulatory factors that assemble the complexes that help them communicate with each other; that’s why it happens as fast as is does - There are common things that get on board that are already joining the RNA polymerase to the moment that transcription happens, the splicing occurs and the poly A addition happens - Certain DNA repair engines an complexes have the same factors that transcription factors have;
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This note was uploaded on 09/14/2011 for the course BIO 362 taught by Professor Walikarzai during the Spring '10 term at SUNY Stony Brook.

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Marcu Lecture 1 - Marcu Lecture 1 - What determines how...

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