Marcu Lecture 4

Marcu Lecture 4 - Marcu Lecture 4 Slide 51-55 - Gcn5 is...

Info iconThis preview shows pages 1–2. Sign up to view the full content.

View Full Document Right Arrow Icon
Marcu Lecture 4 Slide 51-55 - Gcn5 is always a histone acetyl transferase, its never a transcriptional activator - The proteins that are bound to the enhancer/promoter are always activators and are never acetyl transferase - Nucleosome seems to be right at the start site after the TATA box - Gcn5 gets recruited by the activation domains of these proteins that are bound to the enhancers - If they all are not bound to the enchancer you might not recruit gcn5 as effectively - Gcn5 targets the lysine 8 and 9 of H4 for acetylation - After that happens, its possible now that a kinase, it avaialable, is now capable of phosphorylateing serine 10 of H3 - They key is that, if these acetylations did not happen first, even if the kinase was avaialbe and recruited, it cant phosprhorylate serine 10 - First the acetylation has to happen - Part of the reason for this has to do with a recognition signal of the kinase as a not so great substrate and also we believe part of it has to do with the kinase not being able to see the serine, as if the serine was inaccessible to the kinase - When you see these obligatory sequence of events, this is what we call the histone code - After the serine is phosphorulated, tfIID complex can be recruited, and another activator an get recruited and stubstitutes for GCN5 - The purpose of this is to further relax the chromatin of the region - This co-activator has its own histone acetyl transferase, which will acetylate other lysines but not thelysines that have already been acetylated - This means that some acetyl transferae prefer to acetylate some groups and not other ones o Differential effects of histone acetyl trasferase - You need to recruit TFIID even if there is no TATA box, in this case there is one, so the TATA binding protein will help - What you really need is the associated factors of the TATA binding protein, or else TFIIB cannot get to the DNA - The TAFs in the TFIID have mutliple functions, one of which is to making a landing pad for TFIIB - Now that the serine is phosphorylated and the lysines orare acetylated, TFIIB binds better - Of all of the TAFs in the TFIID complex, one of them has a gbromo domain - You recruit the TFIID complex not by the fact of the TATA binding protein, But by the fact that the Tafs have bromo domains that are acetylated - Recruitment of activators mechanism in vivo is not toally dependednt on TATA binding protein - Once more acetylations happen, what is also recreuited is a chromatin remodeling complex is simulatanoeuslt recruited with this and that o You look directly of the promoter on the gene in situ right on the target sequence o Why and how is it simulataenously? o
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Image of page 2
This is the end of the preview. Sign up to access the rest of the document.

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.

Page1 / 4

Marcu Lecture 4 - Marcu Lecture 4 Slide 51-55 - Gcn5 is...

This preview shows document pages 1 - 2. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online