The primary transcript tRNA 5S tRNA TRNA 1 or 2 0-2 R RⅢ RIll- 16s TRNA 23S TRNA
The primary transcript
Ribonucleoprotein核糖核酸蛋白复 合物 RNP complex The precursor rRNA folds up Central domain into stem-loop structures by base pairing in the transcript Some specific proteins bind to the rrna to form rnp complex 5’en s and domain 3’ minor don
Ribonucleoprotein 核糖核酸蛋白复 合物RNP complex • The precursor rRNA folds up into stem-loop structures by base pairing in the transcript • Some specific proteins bind to the rRNA to form RNP complex
Steps in rrna processing rRNA前体被大肠杆菌 RNasel, RNase等 剪切成一定链长的rRNA分子 rRNA在修饰酶催化下进行碱基修饰 rRNA与蛋白质结合形成核糖体的大、小 亚基
Steps in rRNA processing • rRNA前体被大肠杆菌RNaseⅢ,RNaseE等 剪切成一定链长的rRNA分子 • rRNA在修饰酶催化下进行碱基修饰 • rRNA与蛋白质结合形成核糖体的大、小 亚基
Primary rrna processing in prokaryotes Pre-16SrRNA Pre-trNA Pre-23SrRNA Pre-tRNA Pre-5SrRNA Primary m RNase Precursors MaturerrNa
Pre-16S rRNA Pre-t RNA Pre-23S rRNA Pre-tRNA Pre-5S rRNA Precursors Mature rRNA Primary transcript RNase Primary rRNA processing in prokaryotes
Eukaryotic rrna gene organization In the nucleolus, Rna polymerase I transcribes the RNA. which usually exist in tandem repeats containing 100 or more clusters of the transcription units a nucleolus is formed around each cluster RNa polymerase iii transcribes 5s rrna genes: not in cluster with other rrNa genes its gene copy number do not coordinate with other RNa genes Primary transcript 47s, containing ETS external transcribed sequence外部转录间隔区 ITS internal transcribed sequence.部转录间隔区 NTS:non- ranscribed spacer非转录间隔区 Some rrNa genes have intron
Eukaryotic rRNA gene organization • In the nucleolus, RNA polymerase I transcribes the rRNA, which usually exist in tandem repeats containing 100 or more clusters of the transcription units • A nucleolus is formed around each cluster • RNA polymerase III transcribes 5S rRNA genes: not in cluster with other rRNA genes its gene copy number do not coordinate with other RNA genes; • Primary transcript 47S, containing – ETS external transcribed sequence外部转录间隔区 – ITS internal transcribed sequence内部转录间隔区 – NTS: non-transcribed spacer非转录间隔区 • Some rRNA genes have intron