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Isolation and characterization of revertants of the mammalian temperature sensitive leucyl‐tRNA synthetase mutant ts HI
Author(s) -
Molnar S. J.,
Thompson L. H.,
Lofgren D. J.,
Rauth A. M.
Publication year - 1979
Publication title -
journal of cellular physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.529
H-Index - 174
eISSN - 1097-4652
pISSN - 0021-9541
DOI - 10.1002/jcp.1040980209
Subject(s) - transfer rna , mutant , biology , leucine , chinese hamster ovary cell , biochemistry , microbiology and biotechnology , enzyme , aminoacyl trna synthetase , mutation , rna , amino acid , gene , receptor
Nine spontaneous and seven ethyl methanesulfonate induced revertants of the Chinese hamster ovary cell line mutant ( ts Hl), which possesses a temperature sensitive leucyl‐tRNA synthetase, were isolated and characterized with respect to growth rate, leucyl‐tRNA synthetase activity and thermolability, intracellular leucine pool size, and rRNA content. Although most revertants had increased leucyl‐tRNA synthetase activity, and of those tested, all but one had increased thermostability, each appears to be unique. One revertant may be an intergenic suppressor since it appears to contain an elevated level of ts Hl‐like synthetase. There was no evidence for any of the revertants having increased rRNA and tRNA contents, however, many showed leucine pools two to three times larger than wild type cells. Since similar increases have been observed in ts Hl cells they are believed to result from regulation of leucine pool size by the leucyl‐tRNA synthetase and are of a magnitude sufficient to affect significantly the growth of revertants at 38.5°C.