Expression of ubiquitin genes in Chlamydomonas reinhardtii: involvement in stress response and cell cycle

Planta ◽  
1995 ◽  
Vol 197 (3) ◽  
pp. 528-534 ◽  
Author(s):  
Jan von Kampen ◽  
Ute Nieländer ◽  
Michael Wettern
Biomolecules ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 861
Author(s):  
Veronika Kselíková ◽  
Vilém Zachleder ◽  
Kateřina Bišová

Extensive in vivo replacement of hydrogen by deuterium, a stable isotope of hydrogen, induces a distinct stress response, reduces cell growth and impairs cell division in various organisms. Microalgae, including Chlamydomonas reinhardtii, a well-established model organism in cell cycle studies, are no exception. Chlamydomonas reinhardtii, a green unicellular alga of the Chlorophyceae class, divides by multiple fission, grows autotrophically and can be synchronized by alternating light/dark regimes; this makes it a model of first choice to discriminate the effect of deuterium on growth and/or division. Here, we investigate the effects of high doses of deuterium on cell cycle progression in C. reinhardtii. Synchronous cultures of C. reinhardtii were cultivated in growth medium containing 70 or 90% D2O. We characterize specific deuterium-induced shifts in attainment of commitment points during growth and/or division of C. reinhardtii, contradicting the role of the “sizer” in regulating the cell cycle. Consequently, impaired cell cycle progression in deuterated cultures causes (over)accumulation of starch and lipids, suggesting a promising potential for microalgae to produce deuterated organic compounds.


BMC Genomics ◽  
2012 ◽  
Vol 13 (1) ◽  
pp. 215 ◽  
Author(s):  
Guido Mastrobuoni ◽  
Susann Irgang ◽  
Matthias Pietzke ◽  
Heike E Aßmus ◽  
Markus Wenzel ◽  
...  

2019 ◽  
Vol 43 (4) ◽  
pp. 389-400 ◽  
Author(s):  
Séverin Ronneau ◽  
Régis Hallez

ABSTRACTBacteria use dedicated mechanisms to respond adequately to fluctuating environments and to optimize their chances of survival in harsh conditions. One of the major stress responses used by virtually all bacteria relies on the sharp accumulation of an alarmone, the guanosine penta- or tetra-phosphate commonly referred to as (p)ppGpp. Under stressful conditions, essentially nutrient starvation, these second messengers completely reshape the metabolism and physiology by coordinately modulating growth, transcription, translation and cell cycle. As a central regulator of bacterial stress response, the alarmone is also involved in biofilm formation, virulence, antibiotics tolerance and resistance in many pathogenic bacteria. Intracellular concentrations of (p)ppGpp are determined by a highly conserved and widely distributed family of proteins called RelA-SpoT Homologs (RSH). Recently, several studies uncovering mechanisms that regulate RSH activities have renewed a strong interest in this field. In this review, we outline the diversity of the RSH protein family as well as the molecular devices used by bacteria to integrate and transform environmental cues into intracellular (p)ppGpp levels.


mSphere ◽  
2018 ◽  
Vol 3 (6) ◽  
Author(s):  
Kyle R. Pomraning ◽  
Erin L. Bredeweg ◽  
Eduard J. Kerkhoven ◽  
Kerrie Barry ◽  
Sajeet Haridas ◽  
...  

ABSTRACTThe yeastYarrowia lipolyticaundergoes a morphological transition from yeast-to-hyphal growth in response to environmental conditions. A forward genetic screen was used to identify mutants that reliably remain in the yeast phase, which were then assessed by whole-genome sequencing. All thesmoothmutants identified, so named because of their colony morphology, exhibit independent loss of DNA at a repetitive locus made up of interspersed ribosomal DNA and short 10- to 40-mer telomere-like repeats. The loss of repetitive DNA is associated with downregulation of genes with stress response elements (5′-CCCCT-3′) and upregulation of genes with cell cycle box (5′-ACGCG-3′) motifs in their promoter region. The stress response element is bound by the transcription factor Msn2p inSaccharomyces cerevisiae. We confirmed that theY. lipolyticamsn2(Ylmsn2) ortholog is required for hyphal growth and found that overexpression of Ylmsn2enables hyphal growth insmoothstrains. The cell cycle box is bound by the Mbp1p/Swi6p complex inS. cerevisiaeto regulate G1-to-S phase progression. We found that overexpression of either the Ylmbp1or Ylswi6homologs decreased hyphal growth and that deletion of either Ylmbp1or Ylswi6promotes hyphal growth insmoothstrains. A second forward genetic screen for reversion to hyphal growth was performed with thesmooth-33mutant to identify additional genetic factors regulating hyphal growth inY. lipolytica. Thirteen of the mutants sequenced from this screen had coding mutations in five kinases, including the histidine kinases Ylchk1and Ylnik1and kinases of the high-osmolarity glycerol response (HOG) mitogen-activated protein (MAP) kinase cascade Ylssk2, Ylpbs2, and Ylhog1. Together, these results demonstrate thatY. lipolyticatransitions to hyphal growth in response to stress through multiple signaling pathways.IMPORTANCEMany yeasts undergo a morphological transition from yeast-to-hyphal growth in response to environmental conditions. We used forward and reverse genetic techniques to identify genes regulating this transition inYarrowia lipolytica. We confirmed that the transcription factor Ylmsn2is required for the transition to hyphal growth and found that signaling by the histidine kinases Ylchk1and Ylnik1as well as the MAP kinases of the HOG pathway (Ylssk2, Ylpbs2, and Ylhog1) regulates the transition to hyphal growth. These results suggest thatY. lipolyticatransitions to hyphal growth in response to stress through multiple kinase pathways. Intriguingly, we found that a repetitive portion of the genome containing telomere-like and rDNA repeats may be involved in the transition to hyphal growth, suggesting a link between this region and the general stress response.


2018 ◽  
Vol 30 (6) ◽  
pp. 1178-1198 ◽  
Author(s):  
Michal Breker ◽  
Kristi Lieberman ◽  
Frederick R. Cross

1994 ◽  
Vol 14 (8) ◽  
pp. 5165-5174
Author(s):  
J P Davies ◽  
A R Grossman

In Chlamydomonas reinhardtii, transcripts from the beta 2-tubulin gene (tubB2), as well as those from other tubulin-encoding genes, accumulate immediately after flagellar excision as well as at a specific time in the cell cycle. Control of tubB2 transcript accumulation following deflagellation is regulated, at least partially, at the transcriptional level. We have fused the tubB2 promoter to the arylsulfatase (ars) reporter gene, introduced this construct into C. reinhardtii, and compared expression of the chimeric gene with that of the endogenous tubB2 gene. After flagellar excision, transcripts from the tubB2/ars chimeric gene accumulate with kinetics similar to those of transcripts from the endogenous tubB2 gene. The tubB2/ars transcripts also accumulate in a cell cycle-specific manner; however, chimeric transcripts are more abundant earlier in the cell cycle than the endogenous tubB2 transcripts. To elucidate transcriptional control of tubB2, we have mutated or removed sequences in the tubB2 promoter and examined the effect on transcription. The tubB2 promoter shares features with the promoters of other tubulin-encoding genes; these include a GC-rich region between the TATA box and the transcription initiation site and multiple copies of a 10-bp sequence motif that we call the tub box. The tubB2 gene contains seven tub box motifs. Changing the GC-rich region to an AT-rich region or removing three of the seven tub box motifs did not significantly affect transcription of the chimeric gene. However, removing four or five tub box motifs prevented increased transcription following deflagellation and diminished cell cycle-regulated transcription from the tubB2 promoter.


PLoS Genetics ◽  
2020 ◽  
Vol 16 (4) ◽  
pp. e1008600
Author(s):  
Cassandra M. Leech ◽  
Mackenzie J. Flynn ◽  
Heather E. Arsenault ◽  
Jianhong Ou ◽  
Haibo Liu ◽  
...  
Keyword(s):  

2020 ◽  
Vol 10 (10) ◽  
pp. 3797-3810
Author(s):  
Manishi Pandey ◽  
Gary D. Stormo ◽  
Susan K. Dutcher

Genome-wide analysis of transcriptome data in Chlamydomonas reinhardtii shows periodic patterns in gene expression levels when cultures are grown under alternating light and dark cycles so that G1 of the cell cycle occurs in the light phase and S/M/G0 occurs during the dark phase. However, alternative splicing, a process that enables a greater protein diversity from a limited set of genes, remains largely unexplored by previous transcriptome based studies in C. reinhardtii. In this study, we used existing longitudinal RNA-seq data obtained during the light-dark cycle to investigate the changes in the alternative splicing pattern and found that 3277 genes (19.75% of 17,746 genes) undergo alternative splicing. These splicing events include Alternative 5′ (Alt 5′), Alternative 3′ (Alt 3′) and Exon skipping (ES) events that are referred as alternative site selection (ASS) events and Intron retention (IR) events. By clustering analysis, we identified a subset of events (26 ASS events and 10 IR events) that show periodic changes in the splicing pattern during the cell cycle. About two-thirds of these 36 genes either introduce a pre-termination codon (PTC) or introduce insertions or deletions into functional domains of the proteins, which implicate splicing in altering gene function. These findings suggest that alternative splicing is also regulated during the Chlamydomonas cell cycle, although not as extensively as changes in gene expression. The longitudinal changes in the alternative splicing pattern during the cell cycle captured by this study provides an important resource to investigate alternative splicing in genes of interest during the cell cycle in Chlamydomonas reinhardtii and other eukaryotes.


2018 ◽  
Vol 69 (4) ◽  
pp. 622-635.e6 ◽  
Author(s):  
Cindy Meyer ◽  
Aitor Garzia ◽  
Michael Mazzola ◽  
Stefanie Gerstberger ◽  
Henrik Molina ◽  
...  

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