Effects of inhibitors of RNA and protein synthesis on aspartate transcarbamylase activity in etiolated plant tissue [Soybeans, cowpeas]

Aspartate transcarbamylase (ATCase) activity declines in etiolated cowpea (Vigna unguiculata L. Walp.) and soybean (Glycine max L. Merr.) hypocotyls between 3 and 11 days after planting. Treating cowpea hypocotyls with cycloheximide (CH), actinomycin D (AMD), 6-methyl purine (6-MP), or cordycepin in...

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Bibliographic Details
Published in:Plant physiology (Bethesda) 1976-08, Vol.58 (2), p.232-236
Main Authors: Johnson, L.B, Niblett, C.L, Lee, R.F
Format: Article
Language:English
Subjects:
Actinomycin
Enzymes
Gene expression regulation
Hypocotyls
Planting
Protein synthesis
Respiration
RNA
Seedlings
Soybeans
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Summary:Aspartate transcarbamylase (ATCase) activity declines in etiolated cowpea (Vigna unguiculata L. Walp.) and soybean (Glycine max L. Merr.) hypocotyls between 3 and 11 days after planting. Treating cowpea hypocotyls with cycloheximide (CH), actinomycin D (AMD), 6-methyl purine (6-MP), or cordycepin increases ATCase activity up to 740, 350, 465, and 305%, respectively, over water-treated controls 48 to 72 hours after treatment. In contrast erythromycin had no effect, and D-threo-chloramphenicol (CHL) reduced ATCase activity nearly 40%. CH, AMD, and CHL, whose effects were further characterized, each markedly reduced total RNA synthesis and protein synthesis. Respiration was stimulated by CH and AMD and reduced by CHL. In soybean, CHL-treated tissues and water-treated controls had comparable ATCase activities 48 hours after treatment, while AMD, 6-MP, and CH treatments reduced activities 29, 37, and 78%, respectively. The results suggest that the level of ATCase activity in etiolated cowpea hypocotyls is regulated by a mechanism or mechanisms that are interfered with by inhibition of RNA and protein synthesis. Possibly the mechanism is absent from etiolated soybean hypocotyls.
ISSN:0032-0889
1532-2548
DOI:10.1104/pp.58.2.232