Differential regulation of chloroplast gene expression in Chlamydomonas reinhardtii during photoacclimation: Light stress transiently suppresses synthesis of the Rubisco LSU protein while enhancing synthesis of the PS II D1 protein

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Differential regulation of chloroplast gene expression in Chlamydomonas reinhardtii during photoacclimation: Light stress transiently suppresses synthesis of the Rubisco LSU protein while enhancing synthesis of the PS II D1 protein

Year: 

1997

Source of publication :

Plant Molecular Biology

Authors :

Lers, Amnon

.

Volume :

Co-Authors: 

Shapira, M., Department of Life Sciences, Ben-Gurion University of the Negev, P. O. Box 653, Beer Sheva, 84105, Israel
Lers, A., Dept. Post Harvest Sci. Fresh P., Volcani Center, P.O. Box 6, Bet-Dagan, 50250, Israel
Heifetz, P.B., Ciba Agric. Biotechnology Research, 3054 Cornwallis Rd., Res. Triangle Park, NC 27709-2257, United States
Irihimovitz, V., Department of Life Sciences, Ben-Gurion University of the Negev, P. O. Box 653, Beer Sheva, 84105, Israel
Osmond, C.B., Res. School of Biological Sciences, Australian National University, P.O. Box 475, Canberra, ACT 2601, Australia
Gillham, N.W., Departments of Botany and Zoology, Box 91000, Duke University, Durham, NC 27708-1000, United States
Boynton, J.E., Departments of Botany and Zoology, Box 91000, Duke University, Durham, NC 27708-1000, United States

From page: 

1001

To page: 

1011

(

Total pages: 

11

)

Link :

Abstract: 

Transfer of Chlamydomonas reinhardtii cells grown photoautotrophically in low light to higher light intensities has a dramatic transient effect on the differential expression of the two major chloroplast encoded photosynthetic proteins. Synthesis of the D1 protein Photosystem II increases more than 10-fold during the first six hours in high light (HL), whereas synthesis of the large subunit (LSU) of Rubisco drops dramatically within 15 min and only gradually resumes at about 6 h. Synthesis of the chloroplast-encoded ATP synthase β subunit, the nuclear-encoded Rubisco small subunit and the nuclear-encoded β-tubulin is not noticeably affected. Up regulation of psbA mRNA translation accounts for a substantial fraction of the increased D1 synthesis, since accumulation of psbA mRNA increases 4.2- and 6.3-fold less than D1 synthesis at 6 and 18 h in HL. Down-regulation of LSU synthesis is not correlated with a reduction in the steady-state level of the rbcL transcript. Primer extension mapping of the 5' ends of the rbcL mRNAs reveals transcripts with start points located at -93 and -168 relative to the first translated ATG. Transfer of low light (LL)-grown cells to HL temporarily decreases the ratio of the -93 to -168 transcripts, but this ratio normalizeds after 6 h HL, coincident with the recovery in the synthesis of LSU. These several distinct effects of temporary light stress were correlated with a rapid, sustained increase in the reduction state of Q(A), a transient decline in photosynthetic efficiency, a less rapid drop in total chlorophyll content and a delay in cell division.