Light‐regulated expression of the <i>psbA</i> transcript in the cyanobacterium <i>Anacystis nidulans</i>

Lönneborg, Anders; Kalla, Shubhangi; Samuelsson, Göran; Gustafsson, Petter; Öquist, Gunnar

doi:10.1016/0014-5793(88)80349-1

Cited by 34 publications

(18 citation statements)

References 22 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Northern blot analysis and light shift experiments showed that changes in light intensity rapidly and differentially modify the levels of the individual psbA transcripts. The most dramatic light-induced response was the increase (3,19) and would make up virtually all of the psbA signal detected by Lonneborg et al (9). We saw psbAI transcript levels increase after exposure to 50 ,uE m-2 s-for 15 min and remain constant after 30 min.…”

Section: Resultssupporting

confidence: 49%

Different and rapid responses of four cyanobacterial psbA transcripts to changes in light intensity

1990

View full text Add to dashboard Cite

The genome of the cyanobacterium Synechococcus sp. strain PCC 7942 contains three psbA genes which encode two forms of the Dl protein of photosystem II. Experiments using psbA-lacZ translational fusions and Western blot (immunoblot) analysis have shown that the psbA genes respond differently to changes in light intensity, altering the ratio of the two forms of Dl in the thylakoid membrane. Each gene produces a 1.2-kilobase (kb) mRNA. A probe specific for psbAII transcripts also identified a 1.6-kb mRNA which starts 419 base pairs upstream of the 5' end of the 1.2-kb species and overlaps the entire 1.2-kb transcript. This 419-base-pair region includes an open reading frame (ORF1) of 114 amino acids. We investigated the effects of changes in light intensity on psbAII transcript levels in a series of light shift experiments in the wild-type Synechococcus sp. and in AMC084, a mutant which does not produce the 1.6-kb transcript. After exposure to high light intensities for 15 min, the level of the 1.2-kb psbAII transcript increased in both strains. This transcript was not detected in either strain after transfer to low light intensity. The psbAIII transcript showed the same pattern of response as the 1.2-kb psbAII transcript, whereas the 1.6-kb psbAII transcript was unaffected by different light intensities. The psbAI transcript levels responded oppositely to those ofpsbAII and psbAIII. These data, considered along with previous results obtained by using lacZ translational gene fusions, indicate that the response of psbA genes to changes in light intensity is controlled primarily at the transcriptional level.

show abstract

Section: Resultssupporting

confidence: 49%

Different and rapid responses of four cyanobacterial psbA transcripts to changes in light intensity

1990

View full text Add to dashboard Cite

show abstract

“…Because the psbAII and psbAIII genes present in the R2K1 mutant are highly expressed under very high light, it would be very interesting to evaluate whether there exists an environmental adaptation mechanism regulating the response of A. nidulans to extreme light conditions by 'switching' the psbA genes from low and normal light-expressed (psbAI) to high light-expressed (psbAII, psbAIII). A high stability of the level of the Dl transcript has been shown earlier (11). It …”

Section: Recovery From Photoinhibitionmentioning

confidence: 86%

“…Photosynthetic organisms are able to recover from photoinhibition of photosynthesis because of a repair process that occurs when organisms are placed again under favorable growth conditions (13,14,20,21 The process of photoinhibition and recovery in the cyanobacterium Anacystis nidulans has been extensively investigated in our laboratory (10,11,20,21). We have previously shown that A. nidulans responds to photoinhibition in a way similar to higher plants (20).…”

mentioning

confidence: 99%

Photoinhibition and Recovery of Photosynthesis in psbA Gene-Inactivated Strains of Cyanobacterium Anacystis nidulans

Krupa¹,

Öquist²,

Gustafsson³

1990

Plant Physiol.

View full text Add to dashboard Cite

The susceptibility of photosynthesis to photoinhibition and the rate of its recovery were studied in cyanobacterium Anacystis nidulans strain R2 and its two psbA gene-inactivated mutants R2S2C3 and R2K1. Changes in the fluorescence kinetics at 77K as well as the rate of 02 evolution were measured when cells were exposed to high photosynthetic photon flux densities in the range of 0 to 2,000 micromoles per square meter per second.The R2S2C3 mutant has an active psbAl gene highly expressed under low and normal light intensities, whereas R2Kl possesses psbAII and psbAIII genes highly expressed under very high light intensities. The level of overall susceptibility of photosynthesis to photoinhibition was more pronounced in the wild type and the mutant R2S2C3 than in the mutant R2K1, especially at higher light intensities. In contrast, all three strains showed an increased but similar sensitivity to photoinhibition after addition of the translational inhibitor streptomycin; mutant R2K1 being slightly less sensitive at lower light intensities. The result is interpreted as demonstrating similar intrinsic susceptibility to photoinhibition of the two different forms of the Dl protein, form I and form 11, encoded by the psbAl and psbAII/psbAIII genes, respectively.The increased resistance to photoinhibition of the R2K1 mutant was ascribed to an approximately 3 times higher rate of recovery than the wild type and the mutant R2S2C3. On the basis of our experiments we conclude that the susceptibilities to photoinhibition of the Anacystis nidulans psbA genes mutants studied are regulated mainly by modifying the rate of repair, i.e. the rate of turnover of the DI protein.

show abstract

“…strain PCC 6301 and for the unicellular cyanobacterium Synechocystis sp. strain PCC 6803 (22,24,25).…”

mentioning

confidence: 99%

Transcriptional and posttranscriptional components of psbA response to high light intensity in Synechococcus sp. strain PCC 7942

1992

View full text Add to dashboard Cite

The psbA genes, which encode the Dl protein of photosystem II, constitute a multigene family in the cyanobacterium Synechococcus sp. strain PCC 7942. Levels of messages from the three psbA genes change rapidly when cells are shifted from low-light to high-light conditions: the psbAI message level drops, whereas psbAII and psbAIII message levels increase dramatically. We examined the potential contributions of transcriptional and posttranscriptional processes in these high-light responses by subjecting cells that had been grown in a turbidostat at a standard light intensity (130 microeinsteins [1±EJ m-2 s-') to either the same or a higher light intensity (500 ,uE m-2 s-') in the presence or absence of rifampin. Northern (RNA blot) analysis of RNA isolated from cells subjected to high light showed that the increases in psbAII and psbAIII transcripts were blocked by rifampin. This suggests a transcriptional induction of these genes at high light intensities.Increased mRNA stability does not contribute to their accumulation in high-light conditions, since their half-life values did not increase relative to the half-lives measured at the standard light intensity. The rate of disappearance of the psbAI transcript in cells shifted to high light was diminished when either transcription or translation was blocked by rifampin or chloramphenicol, suggesting that accelerated degradation of the message requires de novo synthesis of a protein factor. When rifampin was added 10 min after the shift to high light intensity rather than before the shift, psbAl and psbAIII messages, but not the psbAII message, decayed at a faster rate. Susceptibility of the psbAIII transcript to the high-light-induced factor was also demonstrated by addition of chloramphenicol prior to the shift to high light. psbAIII transcript levels went up more than twofold higher in chloramphenicol-treated cells than in untreated cells, whereas psbAII transcript levels were unaffected by the inhibitor. These experiments provide evidence that either new or increased synthesis of a degradation factor which affects a subset of Synechococcus transcripts occurs in cells subjected to high light intensity.

show abstract

Light‐regulated expression of the psbA transcript in the cyanobacterium Anacystis nidulans

Cited by 34 publications

References 22 publications

Different and rapid responses of four cyanobacterial psbA transcripts to changes in light intensity

Different and rapid responses of four cyanobacterial psbA transcripts to changes in light intensity

Photoinhibition and Recovery of Photosynthesis in psbA Gene-Inactivated Strains of Cyanobacterium Anacystis nidulans

Transcriptional and posttranscriptional components of psbA response to high light intensity in Synechococcus sp. strain PCC 7942

Contact Info

Product

Resources

About