Linked Life Data

12904213

Source:http://linkedlifedata.com/resource/pubmed/id/12904213

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
4
pubmed:dateCreated
2003-8-7
pubmed:abstractText
The barley line albostrians exhibits a severe block in chloroplast development as a result of a mutationally induced lack of plastid ribosomes. White leaves of this mutant contain undifferentiated plastids, possess only traces of chlorophyll (Chl), and are photosynthetically inactive. Chl deficiency, combined with a continuous heme requirement, should lead to drastic changes in the tetrapyrrole metabolism in white versus green leaves. We analyzed the extent to which the synthesis rate of the pathway and the porphyrin distribution toward the Chl- and heme-synthesizing bifurcation is altered in the white tissue of albostrians. Expression and activity of several distinctively regulated enzymes, such as glutamyl-tRNAglu reductase, glutamate 1-semialdehyde aminotransferase, Mg- and Fe-chelatase, and Chl synthetase, were altered in white mutant leaves in comparison to control leaves. A drastic loss in the rate-limiting formation of 5-aminolevulinate and in the Mg-chelatase and Mg-protoporphyrin IX methyltransferase activity, as well as an increase in Fe-chelatase activity, accounts for a decrease in the metabolic flux and the re-direction of metabolites. It is proposed that the tightly balanced control of activities in the pathway functions by different metabolic feedback loops and in response to developmental state and physiological requirements. This data supports the idea that the initial steps of Mg-porphyrin synthesis contribute to plastid-derived signaling toward the nucleus. The barley mutant albostrians proved to be a valuable system for studying regulation of tetrapyrrole biosynthesis and their involvement in the bi-directional communication between plastids and nucleus.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Aug
pubmed:issn
0960-7412
pubmed:author
pubmed:issnType
Print
pubmed:volume
35
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
512-22
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
2003
pubmed:articleTitle
Metabolic control of the tetrapyrrole biosynthetic pathway for porphyrin distribution in the barley mutant albostrians.
pubmed:affiliation
Institut für Biologie/Pflanzenphysiologie, Humboldt Universität, 10155 Berlin, Germany.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't