BIOL 302 1nd Edition Lecture 13Outline of Last Lecture1. Gene Expression2. RNA polymeraseOutline of Current LectureI. Initiation complexII. Typtophan OperonIII. P53IV. EnhancersCurrent LectureI. Initiation complexa. All bind to similar complex and different promoters b. Each has 30,000 genesc. Expressing different subsets in different cell typesd. Not all genes are expressed into cells (differential gene expression)e. Adding growth factor signals the cell to dividei. 30 minutes: 25,000 genes that are turned onf. The cell completely changes – all you need is one cell that triggers the changesi. Controlled by genetic switches that turn on/off genes to transcribe into mRNA or notii. Circadian clock: 24 hours (without any environmental factors)II. Typtophan Operona. Turning genes on/offb. In bacteria (genes are linked and controlled by 1 signal promoter)c. Synthesize enzymes with 5 different genesd. If there’s little or no typtophan then its on, if high then the operon turns off (regulation) – transcriptional regulatione. Sequence binds and represses transcription f. Open turns and RNA bind and makes the transcript. The protein binds to the 2 molecules that binds and activates gene expressiong. Posistive regulation happens more frequently than negative h. Steroid Hormonei. HydrophobicThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.ii. Can get into the cell membrane iii. Can get into a receptor and have a conformational change hat is allowed to enter the nucleus iv. Receptor becomes specific in binding with DNA and activates the transcription initiationv. Breakthrough in breast cancer vi. Estrogen release positive: estrogen receptor (can be negative)1. In breast tissue causes cell division normally that’s okay but if there’s a defect = cancer2. Need a drug to stop the division and what the defect is – killing dividing cells 3. Cells are more sensitive it reduced by 50% and can get a relapse. vii. Sequences bind to specific protein and there are two copies of sp1. Need to have those 3 to be able to turn on (CTP & SP1) viii. In general: all genes are the same thing but to be able to turn on they would have to have a promoter – specific proteinix. Can have many combinations – the protein is the transcription factor – there’s 1000 different binding sequences upstream in genesx. Estrogen receptor can only be activated if estrogen is present in the circadian rhythm III. P53 genei. Protein that binds to DNA and activates gene expression – cellular response to damage by UV light, toxins (environmental factors)1. Breaks in DNA activate DNA pk (protein kinase: phosphorylates p53 when comes in contact with broken DNA)2. The p53 has phosphate to one of its amino acid and changes its structure3. Upstream on TATA boxii. Downstream is not near the promoter and binds the factoriii. SV40: if a virus is going to go into the cell it has to have the right transcription factors. Transcriptional enhances was found through SV40 (72 bp) but 25 different overlapping bindingIV. Enhancers: i. Can function in great distance in great distance from the promoter, happens through looping and can bring them in to contact the transcription factorii. T1 – T9: the number represents sizes with different factors interacts with different