A circadian clock regulates sensitivity to cadmium in Paramecium tetraurelia

Hinrichsen, Robert D.; Tran, Joseph

doi:10.1007/s10565-010-9150-x

Cited by 11 publications

(7 citation statements)

References 57 publications

(64 reference statements)

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“…In addition, the GO analysis of the genes associated with CCA1 peaks in LD conditions also revealed enrichment for genes associated with response to osmotic stress and salinity and with response to metal ions, including cadmium. A link between cadmium and the circadian clock has been observed previously in Arabidopsis and other organisms (40)(41)(42).…”

Section: Countsupporting

confidence: 58%

Genome-wide identification of CCA1 targets uncovers an expanded clock network inArabidopsis

Nagel

Doherty

Pruneda‐Paz

et al. 2015

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

228

279

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The circadian clock in Arabidopsis exerts a critical role in timing multiple biological processes and stress responses through the regulation of up to 80% of the transcriptome. As a key component of the clock, the Myb-like transcription factor CIRCADIAN CLOCK ASSOCIATED1 (CCA1) is able to initiate and set the phase of clockcontrolled rhythms and has been shown to regulate gene expression by binding directly to the evening element (EE) motif found in target gene promoters. However, the precise molecular mechanisms underlying clock regulation of the rhythmic transcriptome, specifically how clock components connect to clock output pathways, is poorly understood. In this study, using ChIP followed by deep sequencing of CCA1 in constant light (LL) and diel (LD) conditions, more than 1,000 genomic regions occupied by CCA1 were identified. CCA1 targets are enriched for a myriad of biological processes and stress responses, providing direct links to clock-controlled pathways and suggesting that CCA1 plays an important role in regulating a large subset of the rhythmic transcriptome. Although many of these target genes are evening expressed and contain the EE motif, a significant subset is morning phased and enriched for previously unrecognized motifs associated with CCA1 function. Furthermore, this work revealed several CCA1 targets that do not cycle in either LL or LD conditions. Together, our results emphasize an expanded role for the clock in regulating a diverse category of genes and key pathways in Arabidopsis and provide a comprehensive resource for future functional studies.genome-wide | circadian clock | clock-controlled outputs | transcriptional regulation I n anticipation of the daily changes in light and temperature, the plant's internal circadian clock regulates a large portion of the transcriptome, nearly 80% in rice, poplar, and Arabidopsis (1, 2). The clock provides temporal coordination of multiple biological functions to ensure optimal efficiency. For example, before dawn, photosynthetic transcripts accumulate in anticipation of the expected sunlight. Even when shifted to constant light (LL) and temperature, in the absence of day/night cues, transcripts associated with photosynthesis are still up-regulated before the subjective day (1-4). Not only are light-and energyrelated activities restricted to particular times, but other aspects of plant growth, including water use, hormone activity, UVB response, and low-temperature response, show this gating effect (5-9). This temporal partitioning of biological responses ultimately provides an optimal integration of the plant's organismal functions with the environment.The circadian clock in plants involves a posttranscriptional component and a well-studied transcriptional-translation feedback regulation between the Myb-like transcription factors CIRCADIAN CLOCK ASSOCIATED 1 (CCA1) and LATE ELONGATED HYPOCOTYL (LHY) and a member of the PSEUDO RESPONSE REGULATOR (PRR) family, TIMING OF CAB2 EXPRESSION 1 (TOC1) (10-16). Together these three components contribute t...

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Section: Countsupporting

confidence: 58%

Genome-wide identification of CCA1 targets uncovers an expanded clock network inArabidopsis

Nagel

Doherty

Pruneda‐Paz

et al. 2015

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

228

279

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“…At the present stage, we presume that the priority may be given to clarify the existence of diurnal variation of susceptibility to metal compounds by many researchers, since there are a few reports examined the Cd-induced chronotoxicity: using mice (in French) (Cambar et al, 1983) or Paramecium tetraurelia (Hinrichsen and Tran, 2010) in addition to our reports (Miura, 2009;Ohtani et al, 2013). The information acquired from these examinations is important for protecting the human health from the hygienic viewpoint.…”

Section: Discussionmentioning

confidence: 72%

Mechanisms of cadmium-induced chronotoxicity in mice

et al. 2013

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-Biological defense factors show diurnal variations in their expression levels or activities. These variations can induce the different sensitivity to external toxicants of a day. We reported earlier that mice showed clear diurnal variation of cadmium (Cd)-induced toxicity, i.e., chronotoxicity. In this report, we investigated additional new evidences for the cadmium (Cd)-induced chronotoxicity, and considered the mechanisms contributed to this chronotoxicity. Male C57BL/6J mice were injected with CdCl 2 (6.4 mg/kg, one shot) intraperitoneally at 6 different time points of a day (zeitgeber time (ZT); ZT2, ZT6, ZT10, ZT14, ZT18 or ZT22) followed by monitoring the mortality until 14 days after the injection. We observed extreme difference in survival numbers: surprisingly, all mice died at ZT2 injection while all mice survived at ZT18 injection. Moreover, in non-lethal dose of Cd (4.5 mg/kg), the values of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) used as indexes of hepatotoxicity markedly increased at ZT6 injection while mostly unchanged at ZT18 injection. To consider the mechanisms of this extreme diurnal variation, we examined biochemical studies and concluded that the diurnal variation was not caused by the differences in hepatic Cd level, basal hepatic metallothionein (MT) level, and induction level or induction speed of hepatic MT. We suggested that one of the candidate determination factors was glutathione. We believe that the "chronotoxicology" for metal toxicity may be classic, yet new viewpoint

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“…Previous studies indicated that mice have a diurnal rhythm of MT-1 and MT-2 mRNA levels [22,23,25]. Hinrichsen and Tan found a circadian variation of Cd toxicity in P. tetraurelia [21] and Miura et al showed a correlation between the diurnal variation of basal hepatic MT protein level in the liver of mice and Cd-induced chronotoxicity [24]. In our study, L. terrestris that were kept at constant light did not show a circadian expression pattern of wMT-2 gene transcription, and no difference in controls and upon Cd exposure was observed (Figure 1).…”

Section: Discussionmentioning

confidence: 99%

“…Furthermore, Cd has a negative effect on wound healing mechanisms shown in L. terrestris [17] and revealed immunosuppressive effects [18,19,20]. Moreover, Hinrichsen and Tran 2010 found that for Paramecium tetraurelia the sensitivity to Cd has been shown to follow a circadian pattern [21]. Cahill, Nyberg, and Ehret showed MT levels and Cd accumulation in mice vary during a 24 h period [22].…”

Section: Introductionmentioning

confidence: 99%

Regulatory Plasticity of Earthworm wMT-2 Gene Expression

Drechsel

Schauer

Šrut

et al. 2017

IJMS

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Metallothioneins (MTs) are multifunctional proteins occurring throughout the animal kingdom. While the expression and transcriptional regulation of MTs is well-studied in vertebrates, the mechanism of MT activation is still unknown for most invertebrates. Therefore, we examined wMT-2 gene regulation and expression patterns in Lumbricus rubellus and L. terrestris. Transcription levels, the occupation of DNA binding sites, the expression of putative transcriptional regulators, and promotor DNA methylation were determined. We found that wMT-2 expression does not follow a circadian pattern. However, Cd-induced wMT-2 induction was observed, and was, interestingly, suppressed by physical injury. Moreover, the promotor region that is responsible for the wMT-2 gene regulation was elucidated. ATF, a putative transcriptional regulator, showed increased phosphorylation upon Cd exposure, suggesting that it plays a major role in wMT-2 gene activation. The promotor methylation of wMT-2, on the other hand, is probably not involved in transcriptional regulation. Elucidating the regulatory mechanism of the earthworm MT gene activation might provide insights into the molecular coordination of the environmental stress response in invertebrates, and might also reveal a link to wound repair and, in a broader sense, to immunity.

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A circadian clock regulates sensitivity to cadmium in Paramecium tetraurelia

Cited by 11 publications

References 57 publications

Genome-wide identification of CCA1 targets uncovers an expanded clock network inArabidopsis

Genome-wide identification of CCA1 targets uncovers an expanded clock network inArabidopsis

Mechanisms of cadmium-induced chronotoxicity in mice

Regulatory Plasticity of Earthworm wMT-2 Gene Expression

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