Development of Ribulose-1,5-Diphosphate Carboxylase in Castor Bean Cotyledons

Dockerty, Alex; Lord, J. Michael; Merrett, M. J.

doi:10.1104/pp.59.6.1125

Cited by 6 publications

(4 citation statements)

References 16 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…However, after day 4 in the dark the rate of RuBPCase accumulation declines, whereas in the light the rate of accumulation is maintained. This is in agreement with the finding that light is not required for the accumulation of RuBPCase in the cotyledons of mustard and castor bean seedlings (11,25). During the time period under study, the cell number of the cotyledons remains constant; (4) hence, all data presented here, expressed on a per cotyledon basis, can in effect be extrapolated to a per cell basis.…”

Section: Resultssupporting

confidence: 78%

Synthesis of Chloroplast Proteins during Germination and Early Development of Cucumber

Walden¹,

Leaver²

1981

Plant Physiol.

View full text Add to dashboard Cite

Cell-free protein synthesizing systems have been used to study the developmental changes in the synthesis of chloroplast proteins in the cotyledons of cucumber seedlings grown in the lght or in the dark. Escherichia coi and wheat germ in vitro protein synthesizing systems have been used to assay the changes in the levels of the mRNA's coding for ribulose 1,5-bisphosphate carboxylase (RuBPCase). The large subunit of cucumber RuBPCase has been identified among the translation products of the E. coli system. The wheat germ system translates the cucumber mRNA coding for the small subunit of RuBPCase to produce a 25,000 molecular weight precursor polypeptide. Plastids isolated from lght-grown cotyledons were used to study developmental changes in their capacity to synthesize protein. The data obtained indicate that in the light there is an initial 48-hour period of accumulation of the mRNA's coding for the large and small subunits of RuBPCase, coupled with an increase in the capacity of the isolated plastids to synthesize protein. This is followed by a decline. This decline is not reflected in the accumulation of RuBPCase in the cotyledons which remains constant over the period of study.The cotyledons of seeds which exhibit epigeal germination provide a useful system to study plastid development. As part of a program to study germination and development of cucumber (Cucumis sativus) seedlings (4) we became interested in the acquisition of photosynthetic competence by the cotyledons. During seedling development, the initial source of energy for the seedling is provided by the metabolism of stored.lipid (4). However, once the cotyledons emerge above the soil there is a decline in the activities of the enzymes that are involved in lipid metabolism. This decline coincides with increases in the levels of phototrophic indicators such as Chl and RuBPCase3 (4). Our aim was to study the control mechanisms involved in the synthesis of chloroplast proteins during the transiti6n of the cotyledon from growth on endogenous reserves to growth on newly fixed carbon.In this paper we describe the use ofcell-free protein synthesizing systems to study developmentally related changes in the levels of translatable mRNAs which code for RuBPCase within the cotyledons of cucumber seedlings. Previous

show abstract

Section: Resultssupporting

confidence: 78%

Synthesis of Chloroplast Proteins during Germination and Early Development of Cucumber

Walden¹,

Leaver²

1981

Plant Physiol.

View full text Add to dashboard Cite

show abstract

“…LHCP protein is undetectable during dark growth, although LHCP mRNA is detectable at very low levels. Illumination of darkgrown leaves leads to rapid induction of all four mRNAs and polypeptides to near normal levels within 24-48 h. Several other studies have followed the appearances in higher plants of LSu and SSu polypeptides or of RuBPCase activity during light or dark development of leaves or cotyledons or during greening of dark-grown leaves (16,(51)(52)(53)(54)(55) . RuBPCase is extremely low or undetectable during dark growth of certain plant species, such as pea, while others species accumulate nearly normal levels.…”

Section: Discussionmentioning

confidence: 99%

Light-regulated gene expression during maize leaf development.

Nelson¹,

Harpster²,

Mayfield³

et al. 1984

The Journal of Cell Biology

185

140

View full text Add to dashboard Cite

We have established schedules of expression during maize leaf development in light and darkness for the messenger RNAs (mRNAs) and polypeptides for ribulose 1,5-bisphosphate carboxylase (RuBPCase) subunits, phosphoenolpyruvate carboxylase (PEPCase), and the light-harvesting chlorophyll a/b-binding protein (LHCP). Levels of mRNAs were measured by hybridization with cloned probes, and proteins were measured by immunodetection on protein gel blots . The initial synthesis in leaves of all four mRNAs follows a lightindependent schedule; illumination influences only the level to which each mRNA accumulates. The synthesis of RuBPCase small and large subunits and of PEPCase polypeptides also follows a light-independent schedule which is modified quantitatively by light. However, the accumulation of LHCP polypeptides absolutely requires illumination. The accumulation of each protein closely follows the accumulation of its mRNA during growth in light. Higher ratios of PEPCase and RuBPCase protein to mRNA occur during dark growth .

show abstract

“…DISCUSSION Proplastids have been isolated from several higher plant tissues (16,29,32,34) but separation of Euglena proplastids from mitochondria was not achieved by zonal centrifugation (22) while urografm gradients were required to obtain an enriched proplastid fraction for ultrastructural studies (28). Minor modification of the method previously used to isolate functional Euglena organelles (12,13) gave a plastid fraction, uncontaminated by mitochondria at an equilibrium density of 1.24 g/cm3, similar to the value obtained for higher plant proplastids (10,16). NADP glyoxylate reductase, a presumptive proplastid enzyme (36), was taken as a marker for plastid integrity (32) and following centrifugation 50%o of the activity was recovered from the soluble fraction showing a 50%o plastid breakage.…”

Section: -mentioning

confidence: 99%

Isolation and Enzymic Characterization of Euglena Proplastids

Dockerty¹,

Merrett²

1979

Plant Physiol.

Self Cite

View full text Add to dashboard Cite

Organelles were isolated from dark-grown Euglena gracilis Klebs by sucrose density gradient centrifugation. Plastids, identified by triosephosphate isomerase and NADP glyoxylate reductase were present at an equilibrium density of 1.24 grams per cubic centimeter clearly separated from mitochondria at an equilibrium density of 1.22 grams per cubic centimeter. Assay for choline phosphotransferase and glucose-6-phosphatase showed that endoplasmic reticulum membranes were present at a density of 1.12 grams per cubic centimeter. The plastid fraction contained phosphofructokinase, pyruvate kinase, triosephosphate isomerase and aldolase indicating the operation of a glycolytic pathway. During regreening pyruvate kinase and phosphofructokinase in the developing proplastid decreased, neither enzyme being present in the mature chloroplast. However, plastids were present in the photosynthetic cell as shown by a peak of glycolysis enzymes at an equilibrium density of 1.24 grams per cubic centimeter.The integrity of isolated plastids was demonstrated by their capacity for protein synthesis. Plastids isolated from dark-grown cells rapidly incorporated [(35)S]methionine into protein with an absolute dependence on added ATP. The large subunit of ribulose diphosphate carboxylase was the major polypeptide synthesized by these isolated plastids.

show abstract

Development of Ribulose-1,5-Diphosphate Carboxylase in Castor Bean Cotyledons

Cited by 6 publications

References 16 publications

Synthesis of Chloroplast Proteins during Germination and Early Development of Cucumber

Synthesis of Chloroplast Proteins during Germination and Early Development of Cucumber

Light-regulated gene expression during maize leaf development.

Isolation and Enzymic Characterization of Euglena Proplastids

Contact Info

Product

Resources

About