Current LectureMCB 250 1st Edition Lecture 17Outline of Current Lecture 1. Eukaryotic Transcription2. Promoter BindingCurrent Lecture3. Eukaryotic Transcription- Eukaryotes have 3 different RNA polymeraseso Pol I: transcribes rRNA geneso Pol II: transcribes all mRNA (protein coding genes) and microRNAo Pol III: transcribes tRNA and small RNA’s- Eukaryotes are monocistronic (no operons) single mRNA = Single gene strung- Transcription and translation are separate in eukaryotes because the separation of the 2processes the mRNA are modified. Caps and splicing- RNA polymerase are similar in prokaryotes and ekaryotes have similar structures, mechanism is similar. Eukaryotes are more complicated and has more subunits, that are equivalent to bacteria polymerase- ICLICKER: Which of the following is accurate with regards to the intron/exon organization of eukaryote transcripts?- !!!! Individual exons can consist of coding sequence, non-coding sequence, or a combination of the two.- X introns are junk DNA and contain no biologically significant info: contains information for splicing and transcription- X each exons has its own start codon (AUG): After splicing, you only need one start codon and the whole protein will be translated from that one splice coding sequence- X Splicing is common to both protein coding MRNA and ribosomal:- X Splice sites fall btwn codons:4. Promoter binding- Prokaryotes have RNA pol with a sigma factor (holoenzyme) that binds the DNA- Eukaryotes contain Pol II core enzyme binds to the promoter with the aid of auxiliary proteins (general transcription factors) The General TFs allow the enzyme to bind at a specific DNA sequence. There are a lot more auxiliary proteins involved in eukaryoteso 1st proteins to bind are TBP “TATA binding proteins” And bends the DNA, followed by TFIIBThese 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.o TFIIH is ATP-Dependent DNA helicase and melts the double stranded DNA so Pol II can initiate transcription.o There are also activator proteins that are bound outside the core promoter that is connected by the mediator to interact with the RNA polymerase IIo Pol II has the tail with 3 serine’s and first the Open complex tail is wrapped around the TFo Once elongation and promoter clearance, the C terminal tail gets
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