Isolation of 45S rRNA-processing intermediates from poliovirus(脊髓灰质炎病毒)-infected HeLa cells Culture cell virus-infected 5000 2000 Incubation with 32S ←-28S isotopes for a 45S short time (pulseoo 1500 n 1 Chase with 母 6 1000 cold 9 0 02000 substrates 20S 中 24 500 Collect samples 1000 and detection at different time 5.0B8888888808 Figure 16.3 0 60 80 100 120 course. Slice number >what intermediates are?How long of its half- lift
Isolation of 45S rRNA—processing intermediates from poliovirus(脊髓灰质炎病毒)-infected HeLa cells Culture cell Incubation with isotopes for a short time (pulse) Collect samples and detection at different time course. ➔ what intermediates are? How long of its halflift ? Chase with cold substrates virus-infected
The rRNA-processing steps are managed in the nucleolus by a class of small nucleolar RNAs (snoRNAs),associated with many proteins in small nucleolar ribonucleoproteins(snoRNPs). There are many hundreds of snoRNAs,but just a few of them participate in rRNA processing.In particular, three snoRNPs (E1.E2,and E3)have been shown to interact with distinct regions in pre-rRNA
The rRNA—processing steps are managed in the nucleolus by a class of small nucleolar RNAs (snoRNAs)，associated with many proteins in small nucleolar ribonucleoproteins(snoRNPs). There are many hundreds of snoRNAs，but just a few of them participate in rRNA processing. In particular， three snoRNPs (E1．E2，and E3) have been shown to interact with distinct regions in pre—rRNA．
小结 核糖体RNA在真核生物细胞核中以前体的形式形成，这 些前体必须被加工才能释放出成熟的rRNAS。 虽然成熟RNA的准确大小在不同物种之间是不同的，但 在所有的真核生物中，前体RNAs的顺序都是18S,5.8S, 28S。在人的细胞中前体是45S,并在加工过程产生41S, 32S和20S的中间产物形式。 snoRNAs在这些加工的过程中起了重要的作用
小结 核糖体RNA在真核生物细胞核中以前体的形式形成，这 些前体必须被加工才能释放出成熟的rRNAs。 虽然成熟rRNA的准确大小在不同物种之间是不同的，但 在所有的真核生物中，前体RNAs的顺序都是18S，5.8S， 28S。在人的细胞中前体是45S，并在加工过程产生41S， 32S和20S的中间产物形式。 snoRNAs在这些加工的过程中起了重要的作用
Prokaryotes ·rrn operons .The bacterium have several rrn operons that contain rRNA genes. rrnD operon 16S 23S 5S tRNA ERNA tRNA Transcription of the rrnD operon yields a 30s precursor,which must be cut up to release the three rRNA and three tRNAs. rRNA processing
Prokaryotes • rrn operons •The bacterium have several rrn operons that contain rRNA genes. tRNA tRNA tRNA Transcription of the rrnD operon yields a 30S precursor, which must be cut up to release the three rRNA and three tRNAs. rRNA processing
rrnD operon 23S rRNA 16S 23S 5S U U Transcription U A 30s precursor Q A A U G complementary Processing(including RNase Ill) A RNase lll- G G RNase Ill U Figurel6.4 RNase E remoy the 5S rRNA from the precursor
30S precursor complementary RNase E remov the 5S rRNA from the precursor Figure16.4