RNA PoSttranscriptional Procession 转录后加工
RNA Posttranscriptional Procession 转录后加工
Classes of rna Pre-RNA, EARNA: The primary transcript has the same organization as the gene hnrNA, heterogeneous nuclear RNA,核内不均一RNA: Eucaryotic RNa Pol Ii transcribes a variety of different genes SnRNA, small nuclear rna,核内小RNA: is any one of many small RNA species confined to the nucleus: several of the snrNas are involved in splicing or other rna processing reactions SCRNA, small cytoplasmic rna,胞内小RNA: several molecules present in the cytoplasm and(sometimes ) nucleus ·rRNA, ribosomal rna,核糖体RNA: Serve as components of ribosomes tRNA: transfer RNA, #ERNA: carrying an amino acid; the covalent linkage is between the nh2 group of the amino acid and either the 3-or 2-oh group of the terminal base of the trNA mRNA, messager RNA, ERNA: carries genetic message from the chromosome to the ribosomes
Classes of RNA • Pre-RNA, 前体RNA: The primary transcript has the same organization as the gene • hnRNA, heterogeneous nuclear RNA, 核内不均一RNA: Eucaryotic RNA Pol II transcribes a variety of different genes • snRNA, small nuclear RNA, 核内小RNA: is any one of many small RNA species confined to the nucleus; several of the snRNAs are involved in splicing or other RNA processing reactions • scRNA, small cytoplasmic RNA, 胞内小RNA: several molecules present in the cytoplasm and (sometimes) nucleus • rRNA, ribosomal RNA, 核糖体RNA: Serve as components of ribosomes • tRNA: transfer RNA, 转移RNA: carrying an amino acid; the covalent linkage is between the NH2 group of the amino acid and either the 3´- or 2´-OH group of the terminal base of the tRNA t • mRNA, messager RNA, 信使RNA: carries genetic message from the chromosome to the ribosomes
Function of rna Class Function Position hnRNa 成熟mRNA的前体 核内 SRNA 参与 hnRNA的剪接、转运 核内 SCRNA 蛋白质内质网定位合成的信胞内 号识别体的组成成分 rRNA 核蛋白体组成成分 trNa 转运氨基酸 mRNA 蛋白质合成模板
Function of RNA Class Function Position hnRNA 成熟mRNA的前体 核内 snRNA 参与hnRNA的剪接、转运 核内 scRNA 蛋白质内质网定位合成的信 号识别体的组成成分 胞内 rRNA 核蛋白体组成成分 tRNA 转运氨基酸 mRNA 蛋白质合成模板
Types of RNa processing A) Cutting and trimming to generate ends rRNA, tRNa and mrNA B)Covalent modification Add a cap and a poly a tail to mRNA Add a methyl group to 2 -oh of ribose in mRNA and rrNA Extensive changes of bases in trNa C) Splicing pre-rRnA, pre-mRNA, pre-trna by different mechanisms
Types of RNA processing • A) Cutting and trimming to generate ends: – rRNA, tRNA and mRNA • B) Covalent modification: – Add a cap and a polyA tail to mRNA – Add a methyl group to 2’-OH of ribose in mRNA and rRNA – Extensive changes of bases in tRNA • C) Splicing – pre-rRNA, pre-mRNA, pre-tRNA by different mechanisms
The long and winding START RNA TRANSCRIPTION POSSIBLE RNA road ATTENUATION transcript CAPPING aborts SPLICING AND nonfunctional 3′- END CLEAVAGE mRNA sequences POSSIBLE RNA EDITING retention and NUCLEAR EXPORT degradation in nucleus SPATIAL LOCALIZATION IN CYTOPLASM START translation TRANSLATION blocked POSSIBLE TRANSLATIONAL RECODING POSSIBLE RNA RNA degraded STABILIZATION CONTINUED PROTEIN SYNTHESIS Figure 7-87. Molecular biology of the cell, 4th edition
The Long and Winding Road…