TY - JOUR
T1 - Ribosomal RNAs are tolerant toward genetic insertions
T2 - Evolutionary origin of the expansion segments
AU - Yokoyama, Takeshi
AU - Suzuki, Tsutomu
N1 - Funding Information:
We are grateful to the Suzuki lab members for fruitful discussion and advice, and especially to Drs Neuza S. Sato and Kei Kitahara for technical support. We would also like to thank Dr Catherine L. Squires (Tufts Univ.) for providing us with valuable strains and plasmids. This work was supported by grants-in-aid for scientific research on priority areas from the Ministry of Education, Science, Sports, and Culture of Japan (to T.S.), the Human Frontier Science Program (RGY23/2003) (to T.S.), and the Global COE Program for Chemistry Innovation (to T.Y.). Funding to pay the Open Access publication charges for this article was provided by the Japan Ministry of Education, Science, Sports and Culture. Funding to pay the Open Access publication charges for this article was provided by the Japan Ministry of Education, Science, Sports and Culture.
PY - 2008/6
Y1 - 2008/6
N2 - Ribosomal RNAs (rRNAs), assisted by ribosomal proteins, form the basic structure of the ribosome, and play critical roles in protein synthesis. Compared to prokaryotic ribosomes, eukaryotic ribosomes contain elongated rRNAs with several expansion segments and larger numbers of ribosomal proteins. To investigate architectural evolution and functional capability of rRNAs, we employed a Tn5 transposon system to develop a systematic genetic insertion of an RNA segment 31 nt in length into Escherichia coli rRNAs. From the plasmid library harboring a single rRNA operon containing random insertions, we isolated surviving clones bearing rRNAs with functional insertions that enabled rescue of the E. coli strain (Δ7 rrn) in which all chromosomal rRNA operons were depleted. We identified 51 sites with functional insertions, 16 sites in 16S rRNA and 35 sites in 23S rRNA, revealing the architecture of E. coli rRNAs to be substantially flexible. Most of the insertion sites show clear tendency to coincide with the regions of the expansion segments found in eukaryotic rRNAs, implying that eukaryotic rRNAs evolved from prokaryotic rRNAs suffering genetic insertions and selections.
AB - Ribosomal RNAs (rRNAs), assisted by ribosomal proteins, form the basic structure of the ribosome, and play critical roles in protein synthesis. Compared to prokaryotic ribosomes, eukaryotic ribosomes contain elongated rRNAs with several expansion segments and larger numbers of ribosomal proteins. To investigate architectural evolution and functional capability of rRNAs, we employed a Tn5 transposon system to develop a systematic genetic insertion of an RNA segment 31 nt in length into Escherichia coli rRNAs. From the plasmid library harboring a single rRNA operon containing random insertions, we isolated surviving clones bearing rRNAs with functional insertions that enabled rescue of the E. coli strain (Δ7 rrn) in which all chromosomal rRNA operons were depleted. We identified 51 sites with functional insertions, 16 sites in 16S rRNA and 35 sites in 23S rRNA, revealing the architecture of E. coli rRNAs to be substantially flexible. Most of the insertion sites show clear tendency to coincide with the regions of the expansion segments found in eukaryotic rRNAs, implying that eukaryotic rRNAs evolved from prokaryotic rRNAs suffering genetic insertions and selections.
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U2 - 10.1093/nar/gkn224
DO - 10.1093/nar/gkn224
M3 - Article
C2 - 18456707
AN - SCOPUS:46349111792
VL - 36
SP - 3539
EP - 3551
JO - Nucleic Acids Research
JF - Nucleic Acids Research
SN - 0305-1048
IS - 11
ER -