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Posttranscriptional regulation by light of the steady-state levels of mature B800-850 light-harvesting complexes in Rhodobacter capsulatus.
- Source :
-
Journal of bacteriology [J Bacteriol] 1988 Feb; Vol. 170 (2), pp. 877-82. - Publication Year :
- 1988
-
Abstract
- Photosynthetic organisms exhibit a variety of responses to changes in light intensity, including differential biosynthesis of chlorophyll-protein complexes. Cultures of Rhodobacter capsulatus grown anaerobically with a low intensity of light (2 W/m2) contained about four times as much B800-850 light-harvesting complex as cells grown under high light intensity (140 W/m2). The mRNA transcripts encoding B800-850 beta and alpha peptides were analyzed by Northern blot (RNA blot), S1 nuclease protection, and capping with guanylyl transferase. It was found that the steady-state levels of B800-850 mRNAs in high-light-grown cultures were about four times as great as in cells grown under low light intensity. Therefore, the lesser amounts of mature B800-850 peptide gene products found in cells grown with high light intensity are the result of a posttranscriptional regulatory process. It was also found that there are two polycistronic messages encoding the B800-850 peptides. These messages share a common 3' terminus but differ in their 5'-end segments as a result of transcription initiation at two discrete sites. Moreover, the half-lives of B800-850 mRNAs were about 10 min in cells grown with high light and approximately 19 min in cultures grown with low light. It is concluded that there must be more frequent initiations of transcription of B800-850 genes in cells grown with high light than in those grown with low light, and that the relative amounts of B800-850 complexes under these conditions are controlled by a translational or posttranslational mechanism.
- Subjects :
- Bacterial Proteins biosynthesis
Cloning, Molecular
Endonucleases
Genes, Bacterial
Half-Life
Nucleic Acid Hybridization
Photosynthesis radiation effects
Photosynthetic Reaction Center Complex Proteins
RNA, Bacterial biosynthesis
RNA, Messenger biosynthesis
Rhodopseudomonas growth & development
Rhodopseudomonas radiation effects
Single-Strand Specific DNA and RNA Endonucleases
Bacterial Proteins genetics
Gene Expression Regulation
Light
Rhodopseudomonas genetics
Transcription, Genetic
Subjects
Details
- Language :
- English
- ISSN :
- 0021-9193
- Volume :
- 170
- Issue :
- 2
- Database :
- MEDLINE
- Journal :
- Journal of bacteriology
- Publication Type :
- Academic Journal
- Accession number :
- 2448296
- Full Text :
- https://doi.org/10.1128/jb.170.2.877-882.1988