Three light-inducible heat shock genes of Chlamydomonas reinhardtii.

Gromoff, Erika Donner von; Treier, Ulrike; Beck, Christoph F.

doi:10.1128/mcb.9.9.3911

Cited by 127 publications

(144 citation statements)

References 47 publications

(60 reference statements)

Supporting

Mentioning

138

Contrasting

Order By: Relevance

“…Heme turnover also will be facilitated by PCYA, which converts BV to PCB. We thus propose that PCB is the bilin signal responsible for induction of a photoprotective transcriptional program, because the genes regulated by exogenous heme treatment in darkness differ from those observed here (51)(52)(53). Our studies demonstrate that cells that lack HMOX1 are poorly equipped to deal with the transition from dark to light because they cannot produce bilins.…”

Section: Discussionmentioning

confidence: 52%

Retrograde bilin signaling enables Chlamydomonas greening and phototrophic survival

Duanmu

Casero

Dent

et al. 2013

Proc. Natl. Acad. Sci. U.S.A.

102

172

View full text Add to dashboard Cite

The maintenance of functional chloroplasts in photosynthetic eukaryotes requires real-time coordination of the nuclear and plastid genomes. Tetrapyrroles play a significant role in plastid-tonucleus retrograde signaling in plants to ensure that nuclear gene expression is attuned to the needs of the chloroplast. Well-known sites of synthesis of chlorophyll for photosynthesis, plant chloroplasts also export heme and heme-derived linear tetrapyrroles (bilins), two critical metabolites respectively required for essential cellular activities and for light sensing by phytochromes. Here we establish that Chlamydomonas reinhardtii, one of many chlorophyte species that lack phytochromes, can synthesize bilins in both plastid and cytosol compartments. Genetic analyses show that both pathways contribute to iron acquisition from extracellular heme, whereas the plastid-localized pathway is essential for light-dependent greening and phototrophic growth. Our discovery of a bilin-dependent nuclear gene network implicates a widespread use of bilins as retrograde signals in oxygenic photosynthetic species. Our studies also suggest that bilins trigger critical metabolic pathways to detoxify molecular oxygen produced by photosynthesis, thereby permitting survival and phototrophic growth during the light period.biliverdin | heme oxygenase | iron homeostasis | oxidative stress | RNA-Seq analysisT he daily light-dark cycle requires all oxygenic photosynthetic species to survive the repeated transition from prolonged darkness to phototrophic metabolism at dawn. Most plants are unable to synthesize chlorophyll in darkness and therefore accumulate photosensitizing chlorophyll precursors at night (1). Sunrise induces an oxidative burst as photosynthesis resumes, so the transition to daylight requires careful coordination of many lightdependent processes. Multiple photoreceptors perform such roles in plants, the most notable being the red-sensing, linear tetrapyrrole (bilin)-based phytochromes and the blue-sensing, flavin-based cryptochromes and phototropins (2-5). Bilins are well-established plant retrograde signals, synthesized in plastids but enabling light sensing by cytosolic phytochromes. Phytochrome photoconversion then triggers nuclear translocation to positively regulate photosynthesis-associated nuclear gene (PhANG) expression (6, 7).Genetic studies suggest that plastids also export negative retrograde signals, metabolites that suppress nuclear gene networks targeted by phytochromes (8-10). Among these metabolites are abscisic acid (ABA) (11), tetrapyrroles (12-14), 3′-phosphoadenosine 5′-phosphate (PAP) (15), β-cyclocitral (16), and methylerythritol cyclodiphosphate (MEcPP) (17). Although hypothetical export of a negative tetrapyrrole signal has received considerable support, biochemical evidence for such a retrograde signal remains equivocal in plants (18)(19)(20). Chlorophyte algae diverged from the streptophyte plant lineage over 500 million years ago but share a common chlorophyll a/b-based photosynthetic lightharvesting app...

show abstract

Section: Discussionmentioning

confidence: 52%

Retrograde bilin signaling enables Chlamydomonas greening and phototrophic survival

Duanmu

Casero

Dent

et al. 2013

Proc. Natl. Acad. Sci. U.S.A.

102

172

View full text Add to dashboard Cite

show abstract

“…Northern blot hybridizations were performed as described (13). All probes were generated by random primed labeling with the High-Prime System (Roche-Boerhinger) and [␣-32 P]dCTP following instructions of the manufacturer.…”

Section: Sequencing Of the C Reinhardtii Rh (Cr-rh) Cdnas And Cloninmentioning

confidence: 99%

“…Then 0.132 volumes of cold KCl (2 M) was added and the lysate was incubated on ice for 20 min. After centrifugation at 12,000 ϫ g for 10 min at 4°C, the supernatant was extracted with phenol and RNA was precipitated with 0.33 volumes of LiCl (8 M) as described (13).…”

Section: Sequencing Of the C Reinhardtii Rh (Cr-rh) Cdnas And Cloninmentioning

confidence: 99%

See 1 more Smart Citation

Rhesus expression in a green alga is regulated by CO ₂

Soupène

King

Feild

et al. 2002

Proc. Natl. Acad. Sci. U.S.A.

139

122

View full text Add to dashboard Cite

The function of the Rhesus (Rh) complex in the human red cell membrane has been unknown for six decades. Based on the organismal, organ, and tissue distribution of Rh proteins, and on our evidence that their only known paralogues, the ammonium and methylammonium transport proteins (also called methylammonium permeases), are gas channels for NH 3, we recently speculated that Rh proteins are biological gas channels for CO 2. Like NH 3, CO2 differs from other gases in being readily hydrated. We have now tested our speculation by studying expression of the RH1 gene in the photosynthetic microbe Chlamydomonas reinhardtii. Expression of RH1 was high for cells grown in air supplemented with 3% CO 2 or shifted from air to high CO2 (3%) for 3 h. Conversely, RH1 expression was low for cells grown in air (0.035% CO 2) or shifted from high CO2 to air for 3 h. These results make viable the hypothesis that Rh1 and Rh proteins generally are gas channels for CO 2.T he Rhesus (Rh) blood group substance is the second most abundant protein in human red cell membranes (Ϸ10 5 copies per cell) (1). The related RhAG and Rh30 proteins, which constitute this complex (2, 3), have only one known paralogue, the ammonium and methylammonium transport (Amt) proteins [also called methylammonium permeases (MEP)] (4). Marini and colleagues (5) reported that both Amt͞MEP proteins and the human RhAG and RhCG proteins are active transporters for NH 4 ϩ . Their conclusion regarding Rh proteins was based on the properties of Saccharomyces cerevisiae strains lacking function of its three MEP proteins and carrying cloned human Rh genes. Contrary to the views of Marini et al., we have provided several lines of evidence that Amt and MEP proteins are gas channels for NH 3 and have speculated that Rh proteins are gas channels for CO 2 (6-9). To test the viability of our speculation regarding Rh, we have studied expression of the RH1 gene in the green alga Chlamydomonas reinhardtii, one of the few microbes to have RH genes. Materials and MethodsMedia and Growth Conditions. C. reinhardtii strains CC125 (137c; nit1 nit2 mtϩ) (10), 4Aϩ (nit1 nit2 mtϩ), and CC124 (nit1 nit2 mtϪ) were maintained at 24°C in TAP medium (11), under continuous illumination (40 mol photons m Ϫ2 s Ϫ1 ). Strain 4Aϩ was kindly provided by J.-D. Rochaix (Univ. of Geneva, Switzerland). For growth in high CO 2 , cells were cultured in 1 l bottles containing 700 ml of TP(-N) medium (TAP medium without acetate and nitrogen; ref. 11) under constant illumination (170 mol photons m Ϫ2 s Ϫ1 ) and were bubbled with air enriched with 3% (vol/vol) CO 2 . The nitrogen source was NH 4 Cl (10 mM), arginine (2.5 mM), or hypoxanthine (2.5 mM), as indicated. For growth in low CO 2 , cultures were bubbled with ordinary air [0.035% (vol/vol) CO 2 ]. Chlorophyll aϩb content was estimated after extracting cells with 96% (vol/vol) ethanol (12).

show abstract

“…Recent studies indicate that the nuclear-encoded hsp22, a chloroplast-associated hsp, and hsp7O in Chlamydomonas are regulated by light at the level of transcript accumulation (11,14). In pea, under heat-shock conditions, the abundance of mRNA corresponding to some low molecular mass hsps was found to vary during the day, indicating a circadian control of their accumulation (20).…”

Section: Identification Of the Transcription Initiationmentioning

confidence: 99%

Structure and Light-Induced Expression of a Small Heat-Shock Protein Gene of Pharbitis nil

et al. 1992

View full text Add to dashboard Cite

To isolate genes that are regulated by a photoperiod that promotes flowering in Pharbitis nil, a cDNA library representing mRNA of induced cotyledons was screened by differential hybridization. The DNA sequence of one cDNA clone isolated by this approach, clone 12L, showed homology to plant small heat-shock protein (hsp) genes. P. nil genomic clones hybridizing to clone 12L were isolated, and the DNA sequences of two P. nil small hsp (shsp) genes, shsp-1 and shsp-2, were determined. The derived amino acid sequences of shsp-1 and shsp-2 showed maximum homology to the 17.9-kD soybean hsp, a member of the class 11 cytoplasmic hsps found in plants. A The physiological processes in floral initiation can be divided into three steps: photoperiodic perception by cotyledons, translocation of induced floral stimulus to the shoot tip where floral initiation takes place, and evocation that results in the commitment of the meristem to form flowers. RNA synthesis in cotyledons, in response to the inductive photoperiod, has been suggested as a necessary part of floral induction in P. nil (1, 31). Recently, more direct molecular approaches have been applied to the study of changes in gene expression associated with the photoperiodic induction of flowering. Both qualitative and quantitative differences were found between translatable mRNAs isolated from cotyledons of plants kept in continuous light and from cotyledons of plants that received an inductive dark period (16).To isolate genes whose expression in P. nil cotyledons is regulated by a photoperiod that leads to flowering, we used a differential screening procedure. We report the isolation, sequence, and expression of one of the genes isolated by this approach. We demonstrate that this gene is a member of a multigene family and can potentially encode a low molecular mass hsp4. Expression of one member of this family is regulated by heat shock and by light, and expression of a related member is regulated only by heat shock. MATERIALS AND METHODS PlantsPharbitis nil plants were grown at 230C for 5 d in coolwhite fluorescent light (145 gE m-2 s-1). At this time, they were subjected to an inductive dark period of 12 or 14 h and were subsequently kept in light for 2 h. The cotyledons were excised, and RNA was extracted as described below. Plants that received a red light night break were exposed to 20 min of red light at the 7th hour of the dark treatment.

show abstract

Three light-inducible heat shock genes of Chlamydomonas reinhardtii.

Cited by 127 publications

References 47 publications

Retrograde bilin signaling enables Chlamydomonas greening and phototrophic survival

Retrograde bilin signaling enables Chlamydomonas greening and phototrophic survival

Rhesus expression in a green alga is regulated by CO ₂

Structure and Light-Induced Expression of a Small Heat-Shock Protein Gene of Pharbitis nil

Contact Info

Product

Resources

About

Three light-inducible heat shock genes of Chlamydomonas reinhardtii.

Cited by 127 publications

References 47 publications

Retrograde bilin signaling enables Chlamydomonas greening and phototrophic survival

Retrograde bilin signaling enables Chlamydomonas greening and phototrophic survival

Rhesus expression in a green alga is regulated by CO 2

Structure and Light-Induced Expression of a Small Heat-Shock Protein Gene of Pharbitis nil

Contact Info

Product

Resources

About

Rhesus expression in a green alga is regulated by CO ₂