The Prokaryotic promoter Determines where transcription begins-what site and which strand of dna acts as template Transcription (a) Promoter Coding sequence of gene ! b)Strong E. coli promoters tyr tRNA TCTCAACGTAACACTTTACAGCGGCG.. CGTCATTTGATATGATGC GCCCCGCTTCCCGA TAAGGG rrn D1 GCCTCCGT ATGCATTTTTCCGCTTGTCTTCCTGA..GCCGACTCCCTATAATGCGCCTCCATCGACACGGCGGAT rrn (DXE)2 CCTGAAATTCAGGGTTGACTCTGAAA'.GAGGAAAGCGTAATATAC GCCACCTCGCGACAGTGAGC rrn E1 CTGCAATTTTTCTATTGCGGCCTGCG.. GAGAACTCCCTATAATGCGCCTCCATCGACACGGCGGAT rn A2 GCAAAAATAAATGCTTGACTCTGTAG.. CGGGAAGGCGTATTATGC. ACACCCCGCGCCGCTGAGAA TAACACCGTGCGTGTTGACTATTTTA. CCTCTGGCGGTGATAATGG. TTGCATGTACTAAGGAGGT λP TATCTCTGGCGGTGTTGACATAAATACCACTGGCGGTGATACTGA.'GCACATCAGCAGGACGCAC T7A3 GTGAAACAAAACGGTTGACAACATGAAGTAAACACGGTACGATGT.ACCACATGAAACGACAGTGA T7A1 TATCAAAAAGAGTATTGACTTAAAGT.CTAACCTATAGGATACTTA. CAGCCA TCGAGAGGGACACG 77A2 AAGATAC, AAATCGCTAGGTAA fd V GATACAAATCTCCGTTGTACTTTGTT..TCGCGCTTGGTATAATCG. CTGGGGGTCAAAGATGAGTG 10 (c)Consensus sequences for all E coli promoters 35 region 15-17 bp 10 TTGACAT TATAAT
The Prokaryotic Promoter Determines where transcription begins – what site and which strand of DNA acts as template
Promoter Structure in Prokaryotes (EColi) Promoter structure in prokaryotes Transcription starts mRN NA at offset o 5- PuPuPuPuPuPUPuPU Promoter Pribnow Box(10) transcription start site 5-m-· Gilbert BoX(30) -30 region 10 region TTGACA TATAAT AACTG ATATTA Ribosomal Prabnow box #1 2o Binding Site(+10) 卫 TGACA TATAAT 828479645345% 799544595196% consensus sequences
Promoter Structure in Prokaryotes (E.Coli) Transcription starts at offset 0. • Pribnow Box (-10) • Gilbert Box (-30) • Ribosomal Binding Site (+10)
Eukaryotic Gene Expression Enhancer Promoter Transcribed Region Terminator Transcription RNA Polymerase II Primary transcript Intron Exonl Exon2 plice Translati Cleave/polyadenylate 7mG Transport Polypeptide mg H An
Eukaryotic Gene Expression Promoter Transcribed Region Terminator Transcription RNA Polymerase II Primary transcript 5’ 3’ Translation Polypeptide N C Enhancer Exon1 Exon2 Intron1 Cap Splice Cleave/Polyadenylate 7mG An 7mG An Transport
Definitions Intron(intervening sequence a nucleotide sequence within a gene that is transcribed into rna but excised before translation Intron size: 50- 20.000 nts Exon A subsegment of a gene that encodes a portion of the final geneproduct. This subsegment remains after processing and is ultimately translated into a polypeptide or incorporated into the structure of an rna molecule Most exons are 1000 nts; majority b/n 100-200 nts Primary transcript with introns
Definitions • Intron (intervening sequence): – a nucleotide sequence within a gene that is transcribed into RNA but excised before translation. – Intron size: 50 – 20,000 nts • Exon: – A subsegment of a gene that encodes a portion of the final geneproduct. This subsegment remains after processing and is ultimately translated into a polypeptide or incorporated into the structure of an RNA molecule. – Most exons are < 1000 nts; majority b/n 100 – 200 nts Primary transcript with introns
Eukaryotic Gene Complexity Yeast Fun large” Eukaryotes introns rare introns common, introns common, LONGER than promoters short relative to adjacent eXons eXons genome promoter/enhancer Promoter/enhancer dense genome dense genome sparse
Eukaryotic Gene Complexity • Yeast – introns rare – promoters adjacent – genome dense • “large” Eukaryotes – introns common, LONGER than exons – Promoter/enhancer – genome sparse • Fungi – introns common, short relative to exons – promoter/enhancer – genome dense