Open AccessProposed involvement of an internal promoter in regulation and synthesis of mitochondrial and cytoplasmic leucyl-tRNA synthetases of Neurospora.
Author(s) -
Patricia Beauchamp,
Edith W. Horn,
S. R. Gross
Publication year - 1977
Publication title -
proceedings of the national academy of sciences of the united states of america
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.011
H-Index - 771
eISSN - 1091-6490
pISSN - 0027-8424
DOI - 10.1073/pnas.74.3.1172
Subject(s) - biology , transfer rna , gene , enzyme , biochemistry , neurospora , mutant , genetics , structural gene , mitochondrion , mitochondrial dna , cytoplasm , aminoacyl trna synthetase , transcription (linguistics) , microbiology and biotechnology , neurospora crassa , rna , linguistics , philosophy
Genetic analysis of an electrophoretic variant of the mitochondrial leucyl-tRNA synthetase [L-leucine:tRNALeu ligase (AMP-forming), EC 6.1.1.4] indicates that it is either an allele of or linked closely to leu-5ts, a mutant that is known to produce a cytoplasmic leucyl-tRNA synthetase with an altered affinity for leucine as well as being deficient in the production of the mitochondrial enzyme. Immunological analysis indicates that the two synthetases have little, if any, structural homology. The pattern of synthesis of the enzymes in leu-5ts revertants, the reciprocal relationship of the production of the two enzymes in response to a negative regulatory element, presumably of mitochondrial origin, as well as the lack of detectable structural homology, led to the proposal that the phenotype of leu-5ts results from a mutational alteration in the structural gene for the cytoplasmic enzyme in a region involved in the initiation of transcription of the adjacent gene for the mitochondrial enzyme.