ISSN:
1365-2958
Source:
Blackwell Publishing Journal Backfiles 1879-2005
Topics:
Biology
,
Medicine
Notes:
We previously described a mutation feeB1 conferring a temperature-sensitive filamentation phenotype and resistance to the calmodulin inhibitor 48/80 in Escherichia coli, which constitutes a single base change in the acceptor stem of the rare tRNA3Leu recognizing CUA codons. We now describe a second mutant, feeA1, unlinked to feeB, but displaying a similar phenotype, 48/80 resistance and a reduced growth rate at the permissive temperature, 30°C, and temperature-sensitive, forming short filaments at 42°C. In the feeA mutant, tRNA3Leu expression (but not that of tRNA1Leu) was reduced approximately fivefold relative to the wild type. We previously showed that the synthesis of β-galactosidase, which unusually requires the translation of 6-CUA codons, was substantially reduced, particularly at 42°C, in feeB mutants. The feeA mutant also shows drastically reduced synthesis of β-galactosidase at the non-permissive temperature and reduced levels even at the permissive temperature. We also show that increased copy numbers of the abundant tRNA1Leu, which can also read CUA codons at low efficiency, suppressed the effects of feeA1 under some conditions, providing further evidence that the mutant was deficient in CUA translation. This, and the previous study, demonstrates that mutations which either reduce the activity of tRNA3Leu or the cellular amount of tRNA3Leu confer resistance to the drug 48/80, with concomitant inhibition of cell division at 42°C.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1111/j.1365-2958.1996.tb02523.x
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