Chapter 12. Synthesis and Processing of RNa Bacterial rNas Eukaryotic RNAS
Chapter 12. Synthesis and Processing of RNA Bacterial RNAs Eukaryotic RNAs ……
Overview of Differences Between Prokaryotic and Eukaryotic Gene Expression and Regulation Prokaryotes Eukaryotes Structure of Single, generally circular Genome found in genome genome sometimes chromosomes nucleosome st accompanied by smaller pieces ructure limits DNA of accessory DNA, like plasmids accessibility Size of genome Relatively small Relatively large Location of Coupled; no nucleoid envelope Nuclear transcription and gene barrier because of cytoplasmic translation transcription prokaryotic cell structure and translation Gene clustering Operons where genes with Operons generally not found similar function are grouped in eukaryotes; each gene has together its own promoter element and enhancer element(s) Default state of on Off transcription DNA structure Highly supercoiled DNA with Highly supercoiled chromatin some associated proteins associated with histones in nucleosomes
Overview of Differences Between Prokaryotic and Eukaryotic Gene Expression and Regulation Prokaryotes Eukaryotes Structure of genome Single, generally circular genome sometimes accompanied by smaller pieces of accessory DNA, like plasmids Genome found in chromosomes;nucleosome st ructure limits DNA accessibility Size of genome Relatively small Relatively large Location of gene transcription and translation Coupled; no nucleoid envelope barrier because of prokaryotic cell structure Nuclear transcription and cytoplasmic translation Gene clustering Operons where genes with similar function are grouped together Operons generally not found in eukaryotes; each gene has its own promoter element and enhancer element(s) Default state of transcription On Off DNA structure Highly supercoiled DNA with some associated proteins Highly supercoiled chromatin associated with histones in nucleosomes
Differences between Prokaryotic and Eukaryotic Gene Expression and Regulation RNA polymerase in prokaryotes can access almost any promoter in a dNa strand without the presence of activators or repressors. Thus, the"ground state"of DNA expression in prokaryotes is said to be nonrestrictive,or on "In eukaryotes, however, the ground state of expression is restrictive in that, although strong promoters might be present, they are inactive in the absence of some sort of recruitment to the promoter by transcription factors From Phillips T: Regulation of transcription and gene expression in eukaryotes Nature Education 2008, 1(1)
Differences Between Prokaryotic and Eukaryotic Gene Expression and Regulation • RNA polymerase in prokaryotes can access almost any promoter in a DNA strand without the presence of activators or repressors. Thus, the "ground state" of DNA expression in prokaryotes is said to be nonrestrictive, or "on." In eukaryotes, however, the ground state of expression is restrictive in that, although strong promoters might be present, they are inactive in the absence of some sort of recruitment to the promoter by transcription factors. From Phillips T: Regulation of transcription and gene expression in eukaryotes. Nature Education 2008, 1(1)
12. 1 Synthesis and processing of bacterial rnas 535 RNA 3 DNA RNA polymerase
12.1 Synthesis and processing of bacterial RNAs
12.1.1 Synthesis of bacterial transcripts 200 400 600 800 1000 1200 C 492515 13083239 951y10651230 1243 Lys 1306 Non-template strand upstream DNA 00 downstream DNA 5b000000050d 939Q9999999 Template strand A DNA RNA hybrid (9bp) Region enclosed by the polymerase 29102130 330400466 109511891260 C 200 400 600 800 1000 1200 1400
12.1.1 Synthesis of bacterial transcripts