Effects of a-amanitin on coordination of two mRNAs of ribulose-bisphosphate carboxylase in greening pea leaves
نویسنده
چکیده
The effects of cr-amanitin on light induction of the two mRNAs of ribulose-bisphosphate carboxylase/oxygenase (RuBisCO) in greening pea leaves were examined. Induction of the nuclear-coded small-subunit mRNA but not of the chloroplast-coded large-subunit mRNA was significantly reduced by a-amanitin, indicating that the steady-state level of the large-subunit mRNA is not directly affected by that of the small subunit. This suggests that there is no direct link between nuclear transcription and light induction of the large-subunit mRNA. The synthesis of RuBisCO was also slowed in proportion to the small-subunit mRNA level, and there was not a large excess of the unassociated large subunit polypeptide. The synthesis of the two subunits is probably coordinated. Thus, the expression of the large subunit is partly controlled at the post-transcriptional level.
منابع مشابه
SYNTHESIS OF THE SMALL SUBUNIT OF RIBULOSE 1, 5-DIPHOSPHATE CARBOXYLASE ON CYTOPLASMIC RIBOSOMES FROM G R E E N I N G BEAN LEAVES J.C. GRAY* and R.G.O. KEKWICK
Ribulose I, 5-diphosphate carboxylase (EC 4.1.1.39) is the most abundant protein in the leaves of higher plants, where it is confined to the chloroplasts. The enzyme is composed of two types of subunits which differ in size [1, 2]. The differential labelling of amino acids in the two subunits on incorporation of 14CO2 by'tobacco leaves suggested the possibility that the two subunits were synthe...
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