Activation of RegB endoribonuclease by S1 ribosomal protein requires an 11 nt conserved sequence.
The T4 RegB endoribonuclease cleaves specifically in the middle of the -GGAG- sequence, leading to inactivation and degradation of early phage mRNAs. In vitro, RegB activity is very weak but can be enhanced 10- to 100-fold by the Escherichia coli ribosomal protein S1. Not all RNAs carrying the GGAG motif are cleaved by RegB, suggesting that additional information is required to obtain a complete RegB target site. In this work, we find that in the presence of S1, the RegB target site is an 11 nt long single-stranded RNA carrying the 100% conserved GGA triplet at the 5' end and a degenerate, A-rich, consensus sequence immediately downstream. Our data support the notion that RegB alone recognizes only the trinucleotide GGA, which it cleaves very inefficiently, and that stimulation of RegB activity by S1 depends on the nucleotide immediately 3' to -GGA-.
Durand
Sylvain
S
Institut Jacques Monod, UMR7592 CNRS-Universités Paris 6 and Paris 7, 2 Place Jussieu, 75251 Paris Cedex 05, France.
Richard
Graziella
G
Bisaglia
Marco
M
Laalami
Soumaya
S
Bontems
François
F
Uzan
Marc
M
D017122:Bacteriophage T4 / Q000201:enzymology / Q000235:genetics*; D001483:Base Sequence; D016384:Consensus Sequence; D017124:Conserved Sequence; D004722:Endoribonucleases / Q000378:metabolism*; D004789:Enzyme Activation; D006147:Guanine / Q000032:analysis; D008969:Molecular Sequence Data; D012367:RNA, Viral / Q000737:chemistry* / Q000378:metabolism*; D012269:Ribosomal Proteins / Q000378:metabolism*; D012689:Sequence Homology, Nucleic Acid; D013379:Substrate Specificity
D012367:RNA, Viral; D012269:Ribosomal Proteins; C015494:ribosomal protein S1; D006147:Guanine; D004722:Endoribonucleases; C407103:T4 RegB endoribonuclease