Cell
Volume 40, Issue 1, January 1985, Pages 171-181
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Article
Differential expression of photosynthesis genes in R. capsulata results from segmental differences in stability within the polycistronic rxcA transcript

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Abstract

We report that the light-harvesting and reaction center genes in the rxcA locus of R. capsulata are contained within a single operon and that their differential expression results predominantly from marked segmental differences in stability within the polycistronic rxcA transcript. The 3′ portion of this transcript is rapidly degraded to give rise to either of two slowly decaying mRNA remnants, both of which encode only the light-harvesting polypeptides. The greater stability of these remnants accounts for nearly all of the difference between the concentrations of the light-harvesting and reaction center proteins. The unstable 3′ portion of the transcript is delimited by two alternative stem-and-loop structures, which apparently act as barriers to 3′ exoribonucleases and thereby protect the upstream RNA segment. When a DNA fragment containing the rxcA locus was fused to a plasmid promoter and transcribed in E. coli, the long precursor transcript was processed to two short messages of greater stability, as in R. capsulata.

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  • Cited by (0)

    Present address: Department of Microbiology, University of British Columbia, Vancouver, British Columbia V6T 1W5, Canada.

    Present address: Unit for Applied Cell and Molecular Biology, University of Umeå, Umeå S-901 87, Sweden.

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