title: Multiple in vivo pathways for Escherichia coli small ribosomal subunit assembly occur on one pre-rRNA.
abstract: Processing of transcribed precursor ribosomal RNA (pre-rRNA) to a mature state is a conserved aspect of ribosome biogenesis in vivo. We developed an affinity-purification system to isolate and analyze in vivo-formed pre-rRNA-containing ribonucleoprotein (RNP) particles (rRNPs) from wild-type E. coli. We observed that the first processing intermediate of pre-small subunit (pre-SSU) rRNA is a platform for biogenesis. These pre-SSU-containing RNPs have differing ribosomal-protein and auxiliary factor association and rRNA folding. Each RNP lacks the proper architecture in functional regions, thus suggesting that checkpoints preclude immature subunits from entering the translational cycle. This work offers in vivo snapshots of SSU biogenesis and reveals that multiple pathways exist for the entire SSU biogenesis process in wild-type E. coli. These findings have implications for understanding SSU biogenesis in vivo and offer a general strategy for analysis of RNP biogenesis.
authors.affiliation: Department of Biology, University of Rochester, Rochester, New York, USA.
authors.forename: Neha
authors.initials: N
authors.lastname: Gupta
authors.affiliation: 1] Department of Biology, University of Rochester, Rochester, New York, USA. [2] Center for RNA Biology, University of Rochester, Rochester, New York, USA.
authors.forename: Gloria M
authors.initials: GM
authors.lastname: Culver
mesh_terms: D004926:Escherichia coli / Q000235:genetics* / Q000378:metabolism; D059370:RNA Folding; D012322:RNA Precursors / Q000235:genetics*; D012336:RNA, Ribosomal, 16S / Q000235:genetics*; D012261:Ribonucleoproteins / Q000032:analysis* / Q000302:isolation & purification; D054680:Ribosome Subunits, Small, Bacterial / Q000235:genetics* / Q000378:metabolism
chemical_list: D012322:RNA Precursors; D012336:RNA, Ribosomal, 16S; D012261:Ribonucleoproteins