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The recognition by RNase P of precursor tRNAs
M F Baer1, R M Reilly, G M McCorkle
1Department of Biology, Yale University, New Haven, Connecticut 06520.
The Journal of Biological Chemistry
|February 15, 1988
Summary
Mutations in Escherichia coli RNase P
Area of Science:
- Molecular Biology
- Biochemistry
- Genetics
Background:
- RNase P is a ribozyme essential for tRNA maturation.
- M1 RNA is the catalytic subunit of E. coli RNase P.
- Specific sequences in M1 RNA and tRNA are involved in precursor recognition.
Purpose of the Study:
- To investigate the role of base pairing interactions between M1 RNA and tRNA precursors.
- To analyze the in vitro and in vivo functions of M1 RNA mutants.
Main Methods:
- Site-directed mutagenesis of M1 RNA (A333C, A334U).
- In vitro enzymatic assays using wild-type and mutant M1 RNA with tRNA precursors.
- In vivo complementation assays in a temperature-sensitive RNase P mutant strain.
Main Results:
- M1 RNA mutations (C333, U334) showed reduced activity on wild-type tRNA precursors in vitro.
- A specific tRNA precursor mutant did not restore the activity of the U334 M1 RNA mutant.
- Mutant M1 RNAs failed to complement a temperature-sensitive mutation in the RNase P protein in vivo.
Conclusions:
- Base-pairing interactions between nucleotides 331-335 of M1 RNA and the tRNA GT psi C motif are likely not essential for catalytic cleavage.
- These mutations affect the overall function of M1 RNA in both in vitro and in vivo settings.