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Determinants in the rpsT mRNAs recognized by the 5′‐sensor domain of RNase E
Author(s) -
Mackie George A.
Publication year - 2013
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1111/mmi.12283
Subject(s) - rnase p , biology , cleavage (geology) , rnase ph , rnase h , rnase mrp , messenger rna , ribonuclease iii , rna , cleavage factor , biochemistry , limiting , microbiology and biotechnology , gene , rna interference , mechanical engineering , paleontology , fracture (geology) , engineering
Summary RNase E plays a central role in processing virtually all classes of cellular RNA in many bacterial species. A characteristic feature of RNase E and its paralogue RNase G , as well as several other unrelated ribonucleases, is their preference for 5′‐monophosphorylated substrates. The basis for this property has been explored in vitro . At limiting substrate, cleavage of the rpsT mRNA by RNase E (residues 1–529) is inefficient, requiring excess enzyme. The rpsT mRNA is cleaved sequentially in a 5′ to 3′ direction, with the initial cleavage(s) at positions 116/117 or 190/191 being largely driven by direct entry, independent of the 5′‐terminus or the 5′‐sensor domain of RNase E . Generation of the 147 nt 3′‐limit product requires sequential cleavages that generate 5′‐monophosphorylated termini on intermediates, and the 5′‐sensor domain of RNase E . These requirements can be bypassed with limiting enzyme by deleting a stem‐loop structure adjacent to the site of the major, most distal cleavage. Alternatively, this specific cleavage can be activated substantially by a 5′‐phosphorylated oligonucleotide annealed 5′ to the cleavage site. This finding suggests that monophosphorylated small RNAs may destabilize their mRNA targets by recruiting the 5‐sensor domain of RNase E ‘in trans’.