Handout 7.28

Prokaryotes vs. Eukaryotes: A view from the DNA. (or Why you arent a bacterium). Prokaryote Eukaryote General: Site of Transcription Protoplasm Nucleus Site of DNA Replication Protoplasm Nucleus Site of RNA Splicing Rare Nucleus Site of Translation Protoplasm Cytoplasm Site of Recombination Protoplasm Nucleus DNA Replication: Chromosomes Circular, One Origin Linear, Multiple Origins Telomeres No Yes Replication Machinery DNA Polymerases DNA Pol III (Replication) DNA Pol , DNA Pol Primase dnaG DNA Pol /Primase Helicase dnaB MCM proteins Sliding Clamp -protein PCNA Clamp Loader -complex RF-C Single Stranded DNA Binding Prot. SSB RF-A Polymerase Coupling ? Origin Recognition dnaA ORC Homologous Recombination: function in DSB repair Function in DSB repair, and genetic exchange genetic exchange and chromosome segragation in meiosis. Strand exchange protein RecA RecA homologs (DMC1, Rad51) DSB initiator no specific protein Spo11 Transcription: RNA Polymerases RNAP (Multiple -subunits) RNA Pol I (rRNA) RNA Pol II (mRNA) RNA Pol III (tRNA, snRNA) Termination Intrinsic Terminators Poorly Understood Core Promoter Structure -35 and -10 elements TATA and Initiator Long Distance Activation Rare Common

Handout 7.28

Handout 7.28

Translation: Ribosomes 30S, 50S 40S, 60S mRNA Polycistronic Monocistronic Ribosome binding Shine/Delgarno+AUG 5 Cap+AUG Transcriptional Attenutation Yes No Auxilliary Factors Initiation IF1, IF2, and IF3 eIF1, EIF2, eIF3, eIF4, eIF5 Elongation EF-Tu, EF-G, EF-Ts eEF1a, eEF2, eEF1b Termination RF-1, RF-2, RF-3 eRF-1 (works with all terminators) eRF-3 RNA Splicing: Rare Common self-splicing only Spliceosome-mediated (+ some self-splicing especially in organelles)