Evidence for structural gene alterations affecting aminoacyl-tRNA synthetases in CHO cell mutants and revertants

Larry H. Thompson, Don J. Lofgren, Gerald M. Adair

Research output: Contribution to journalArticle

15 Citations (Scopus)

Abstract

Aminoacyl-tRNA synthetase (aaRS) activities in extracts of mutant strains of the Chinese hamster ovary line (CHO) were examined for alterations in thermal stability. Mutants having low activity for MetRS, AsnRS, or GlnRS contained aaRSs that were inactivated much more rapidly upon heating than those from wild-type cells. Revertant lines, isolated from cultures of these mutants (Asn-5, Met-2, and Gln-2) after treatment with nitrosoguanidine or ethyl methanesulfonate, had thermolabilities intermediate between mutant and wild-type, and consistently had higher activities than the mutants. With a modified in vivo aminoacylation procedure, two previously exceptional mutants, Arg-1 and His-1, showed pronounced reductions in the amount of arginyl-tRNA or histidyl-tRNA, respectively, under restrictive conditions, compared to wild type. Revertants of Arg-1 (like the mutant itself) had no measurable ArgRS in vitro activity (<0.4% of wild type) although in vivo aminoacylation in the one revertant tested was partially restored. These data provide evidence that the forward mutations have occurred in the structural genes of the aaRSs and that most of the reversions are probably the result of second-site point mutations in the aaRS genes.

Original languageEnglish (US)
Pages (from-to)423-435
Number of pages13
JournalSomatic Cell Genetics
Volume4
Issue number4
DOIs
StatePublished - Jul 1978
Externally publishedYes

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Aminoacylation
Amino Acyl-tRNA Synthetases
glutaminyl-tRNA synthetase
Transfer RNA
Cricetulus
Ovary
Nitrosoguanidines
Ethyl Methanesulfonate
Point Mutation
Heating
Genes
Hot Temperature
Mutation
In Vitro Techniques

ASJC Scopus subject areas

  • Genetics
  • Medicine(all)

Cite this

Evidence for structural gene alterations affecting aminoacyl-tRNA synthetases in CHO cell mutants and revertants. / Thompson, Larry H.; Lofgren, Don J.; Adair, Gerald M.

In: Somatic Cell Genetics, Vol. 4, No. 4, 07.1978, p. 423-435.

Research output: Contribution to journalArticle

Thompson, Larry H. ; Lofgren, Don J. ; Adair, Gerald M. / Evidence for structural gene alterations affecting aminoacyl-tRNA synthetases in CHO cell mutants and revertants. In: Somatic Cell Genetics. 1978 ; Vol. 4, No. 4. pp. 423-435.
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