Structure and synthesis of the ribosomal ribonucleic acid of prokaryotes.

INTRODUCTION ........................................................... 562 GENERAL FEATURES OF PROKARYOTIC RIBOSOMES ....... ............... 563 Diversity in Bacterial Ribosomes .................... ............................ 563 STRUCTURES OF THE PROKARYOTIC rRNA MOLECULES ...... ............ 564 Prokaryotic rRNA Molecules................................................... 564 rRNA Integrity and Ribosome Function ............ ............................. 565 Eukaryotic Analogy ........................................................... 565 Base Compositions ofrRNA from Prokaryotes .......... ......................... 565 Primary and Secondary Structures of the rRNA ......... ........................ 568 Question of Functional Heterogeneity in the rRNA Molecules ...... .............. 569 Phylogenetic Differences in the rRNA of Prokaryotes ........ .................... 570 Prokaryotic Origin for the Eukaryotic Organelles? ........ ...................... 572 GENES SPECIFYING rRNA ..................................................... 573 Gene Dosage for rRNA .......................................................... 573 Mapping the rRNA Genes in E. coli ...... ........ .............................. 573 Mapping the rRNA Genes in B. subtilis ......................................... 575 Isolation of the rDNA .......... ............................... 575 General Features of the Prokaryotic Ribosomes ................... .............. 591 Structures of the Prokaryotic rRNA Molecules .................................. 591 Genes Specifying rRNA ........... .............................. 591 Transcription of the rRNA Genes .......................................... 592 Post-Transcriptional Processing of rRNA ....................................... 592 TRANSCRIPTION OF THE rRNA GENES ....................................... 576 rRNA Transcriptional Unit ............... .......................... 576 Interaction of the RNA Polymerase with the rDNA .............. ................ 577 Initiation of rDNA Transcription .......................................... 578 Regulation ofrRNA Synthesis During Balanced Growth ....... ................. 579 Regulation of rRNA Synthesis During Perturbation of Balanced Growth ........ 581 Regulation ofrRNA Synthesis During Morphogenesis ....... .................... 582 POST-TRANSCRIPTIONAL PROCESSING OF rRNA ....... .................... 583 Hypothetical Tandem Transcript of the rDNA .......... ......................... 583 Immediate Precursors of the rRNA Molecules .......... ......................... 584 Function of the Precursor-Specific Sequences .......... ......................... 587 Post-Transcriptional Modification of Nucleosides ......... ...................... 588 Interaction of the rRNA with the Ribosomal Proteins ............................ 589 CONCLUDING COMMENTS ................... ........................ 590 SUMMARY ........................................... 591 ACKNOWLEDGMENTS .............. ............................. 592 ADDENDUM IN PROOF 593 LITERATURE CITED ............................................................ 593