Query (optional)   in Class  

GrainGenes Reference Report: PCP-35-907

[Submit comment/correction]

Reference
PCP-35-907
Title
The onset of 70S chloroplast ribosome formation is determined by an early heat-sensitive stage in the ontogeny of rye leaves
Journal
Plant and Cell Physiology
Year
1994
Volume
35
Pages
907-916
Author
Berberich T
Feierabend J
Abstract
The formation of plastidic 70S ribosomes can be specifically eliminated in developing leaves of rye (Secale cereale L.) when seedlings are continuously grown at an elevated temperature of 32 degrees C Labeling experiments with [35S]methionine and [3H]uridine have indicated that in fully differentiated leaf tissue grown under permissive conditions (22 degrees C) exposure to 32 degrees C did not impair current 70S ribosome biosynthesis Neither the synthesis or processing of plastidic rRNA nor the synthesis and integration of proteins into 70S ribosomes were directly affected However, when the leaves were grown at 32 degrees C, the young tissue of the basal growing zone that had been newly formed during a 24 h or longer heat exposure appeared to become unable to assemble and accumulate 70S ribosomes, whereas all ribosomal constituents that were examined were still present Complete plastid ribosomes were thus progressively diluted out This heat-sensitivity in- dicates the existence of an early step in the differentiation of leaf cells which controls the expres- sion of some limiting factor for plastid ribosome formation or assembly The expression of plastid ribosome constituents was not tightly coregulated. Only after prolonged and extensive depletion of 70S ribosomes were plastidic transcripts (rRNA) diminished and several ribosomal proteins lost. Several nuclear-encoded ribosomal proteins and the transcript for the nuclear-en- coded protein L12 were maintained at high levels in 70S ribosome-deficient leaf sections.
Keyword
cell-differentiation
[ Show all 11 ]

GrainGenes is a product of the Agricultural Research Service of the US Department of Agriculture.