D. Post Transcription1. mRNA is very unstablea) nucleases destroy it very easily- start at the ends and begins chewing2. Post transcriptional modifications must be madea) G-cap- guanine Nucleotide is added 5’ to 5’  not easily recognized by nucleases(1) Guanine used here is mono-methylated, not necessarily guanine(2) 10 nucleotides upstream from the 3’ end of the 3’ non-coding region see AATAAA.. the sequence of the transcript is AAUAAA(3) AAUAAA is a signal sequence for some other molecule to come in and cut off over transcription(4) UsnRNA + proteins= UsnRNP – this has the catalytic ability to recognize AAUAAA sequence and cut the gene off at the 589 markb) Poly-A-tail- poly-A-synthetase recognizes the 3’ end and will one-at-a-time add adenine nucleotides with ATP (a LOT of energy used here)(1) Adds until about 510 nucleotides are added in length(2) stabilizes 3’ end and makes less susceptible to degradation by nucleases(3) allows it to go from the nucleus to the cytoplasm to be translated(4) 85% of the mRNA will have a Poly-A-tail and 15% have a hair pin loop like in prokaryotesE. Translation1. translation begins right after 5’ end of non-coding region with ‘AUG’3. Coding regiona) small portion will not be retained in the mature RNA(1) 2 nucleotides on either side signals an RNP to remove the code – RNP is called spliceosome(2) intron= portion of RNA removed(3) exon= portion of RNA that remains (exon is expressed)(4) mature RNA= RNA without intron in it that can be transported from the nucleus to the cytoplasm as is to be translated (anything else= still immature)(a) because the transcript no longer looks like the gene after it is modified, it is that much harder to match it back to the genome(b) Genome= genetic code sequence, transcriptome- transcription of the gene code, protienome= translated transcriptome(5) UsnRNA is only 100 nucleotides in length and there is 100% conservation in it, we have the same Usn RNA as an earthworm – UsnRNA also has a G-cap but it is trimethylated(a) ** pay attention UsnRNA never has a non-coding region because it never binds to ribosomes4. Promoter region in Eukaryotic RNAa) 20-30 nucleotides upstream= TATA – conserved sequence always present to be recognized by RNA polymerase II and tells it where to startb) 70-80 nucleotides upstream = CAAT – will not tell where to bind but how often to bind, with association to this, there are transcription factors (proteins, steroids etc.)c) further upstream= enhancers – slightly different function can bind to transcription factor that can attract the protein that unwinds the DNABY 330 1st Edition Lecture 10 Outline of Last Lecture C. TranscriptionOutline of Current Lecture D. Post TranscriptionE. TranslationCurrent Lecture**Important note:Globin GeneCode Gene count: 589mRNA: 700 genesprotein: 146 amino acids, 438 nucleotidesD. Post Transcription 1. mRNA is very unstablea) nucleases destroy it very easily- start at the ends and begins chewing 2. Post transcriptional modifications must be madea) G-cap- guanine Nucleotide is added 5’ to 5’  not easily recognized by nucleases (1) Guanine used here is mono-methylated, not necessarily guanine(2) 10 nucleotides upstream from the 3’ end of the 3’ non-coding region see AATAAA.. the sequence of the transcript is AAUAAA (3) AAUAAA is a signal sequence for some other molecule to come in and cut off over transcription These 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.(4) UsnRNA + proteins= UsnRNP – this has the catalytic ability to recognize AAUAAA sequence and cut the gene off at the 589 mark b) Poly-A-tail- poly-A-synthetase recognizes the 3’ end and will one-at-a-time add adenine nucleotides with ATP (a LOT of energy used here)(1) Adds until about 510 nucleotides are added in length (2) stabilizes 3’ end and makes less susceptible to degradation by nucleases(3) allows it to go from the nucleus to the cytoplasm to be translated (4) 85% of the mRNA will have a Poly-A-tail and 15% have a hair pin loop like in prokaryotes E. Translation1. translation begins right after 5’ end of non-coding region with ‘AUG’3. Coding regiona) small portion will not be retained in the mature RNA(1) 2 nucleotides on either side signals an RNP to remove the code – RNP is called spliceosome(2) intron= portion of RNA removed (3) exon= portion of RNA that remains (exon is expressed)(4) mature RNA= RNA without intron in it that can be transported from the nucleus to the cytoplasm as is to be translated (anything else=still immature)(a) because the transcript no longer looks like the gene after it is modified, it is that much harder to match it back to the genome (b) Genome= genetic code sequence, transcriptome- transcription of the gene code, protienome= translated transcriptome(5) UsnRNA is only 100 nucleotides in length and there is 100% conservation in it, we have the same Usn RNA as an earthworm – UsnRNA also has a G-cap but it is trimethylated(a) ** pay attention UsnRNA never has a non-coding region because it never binds to ribosomes 4. Promoter region in Eukaryotic RNAa) 20-30 nucleotides upstream= TATA – conserved sequence always presentto be recognized by RNA polymerase II and tells it where to startb) 70-80 nucleotides upstream = CAAT – will not tell where to bind but how often to bind, with association to this, there are transcription factors (proteins, steroids etc.) c) further upstream= enhancers – slightly different function can bind to transcription factor that can attract the protein that unwinds the