The response time of transcription and translation of the leu-2 gene of Neurospora to its inducer, alpha-isopropylmalate, approaches the permissible minimum.
The rate of transcription and translation of the leu-2 gene of Neurospora crassa was measured after induction by alpha-isopropylmalate. Little message of enzyme was found before inducer addition but transcription in the lower eukaryote was found well underway within five minutes after inducer addition, followed in a minute or two by the appearance of functional enzyme. The timing was close to the limit set by RNA synthesis and ribosome procession. As a consequence, it seems unlikely that traversal of the cell and/or nuclear membranes by the inducer and message involves intermediate synthetic reactions and that the leu-3 positive regulatory element is fully available for participation in the induction process before the inducer is added. A significant overshoot in message synthesis was found early in the induction process. This is discussed with respect to previously observed effects of the inducer on general RNA synthesis.
Mary
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A
Dept. of Biochemistry, Duke University, Durham, N.C. 27710.
Kidd
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GL
Gross
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SR
D005786:Gene Expression Regulation; D005796:Genes / Q000187:drug effects*; D005800:Genes, Fungal / Q000187:drug effects*; D006836:Hydro-Lyases / Q000096:biosynthesis* / Q000235:genetics; D007700:Kinetics; D007930:Leucine / Q000096:biosynthesis*; D008293:Malates / Q000494:pharmacology*; D009491:Neurospora / Q000235:genetics*; D009492:Neurospora crassa / Q000187:drug effects / Q000201:enzymology / Q000235:genetics*; D014176:Protein Biosynthesis / Q000187:drug effects*; D013997:Time Factors; D014158:Transcription, Genetic / Q000187:drug effects*
D008293:Malates; C005906:alpha-isopropylmalate; D006836:Hydro-Lyases; C021455:3-isopropylmalate dehydratase; D007930:Leucine