scholarly journals Limits to the cellular control of sequestered cryptophyte prey in the marine ciliate Mesodinium rubrum

2020 ◽  
Author(s):  
Andreas Altenburger ◽  
Huimin Cai ◽  
Qiye Li ◽  
Kirstine Drumm ◽  
Miran Kim ◽  
...  

AbstractThe marine ciliate Mesodinium rubrum is famous for its ability to acquire and exploit chloroplasts and other cell organelles from some cryptophyte algal species. We sequenced genomes and transcriptomes of free-swimming Teleaulax amphioxeia, as well as well-fed and starved M. rubrum in order to understand cellular processes upon sequestration under different prey and light conditions. From its prey, the ciliate acquires the ability to photosynthesize as well as the potential to metabolize several essential compounds including lysine, glycan, and vitamins that elucidate its specific prey dependency. M. rubrum does not express photosynthesis related genes itself, but elicits considerable transcriptional control of the acquired cryptophyte organelles. This control is limited as light dependent transcriptional changes found in free-swimming T. amphioxeia got lost after sequestration. We found strong transcriptional rewiring of the cryptophyte nucleus upon sequestration, where 35% of the T. amphioxeia genes were significantly differentially expressed within well-fed M. rubrum. Qualitatively, 68% of all genes expressed within well-fed M. rubrum originated from T. amphioxeia. Quantitatively, these genes contributed up to 48% to the global transcriptome in well-fed M. rubrum and down to 11% in starved M. rubrum. This tertiary endosymbiosis system functions for several weeks, when deprived of prey. After this point in time, the ciliate dies if not supplied with fresh prey cells. M. rubrum represents one evolutionary way of acquiring photosystems from its algal prey, and might represent a step on the evolutionary way towards a permanent tertiary endosymbiosis.

2020 ◽  
Author(s):  
Andreas Altenburger ◽  
Huimin Cai ◽  
Qiye Li ◽  
Kirstine Drumm ◽  
Miran Kim ◽  
...  

2021 ◽  
Author(s):  
Andreas Altenburger ◽  
Huimin Cai ◽  
Qiye Li ◽  
Kirstine Drumm ◽  
Miran Kim ◽  
...  

2016 ◽  
Vol 397 (5) ◽  
pp. 417-436 ◽  
Author(s):  
Jessica Nüße ◽  
Ursula Mirastschijski ◽  
Mario Waespy ◽  
Janina Oetjen ◽  
Nadine Brandes ◽  
...  

Abstract Hepatoma-derived growth factor (HDGF) is involved in diverse, apparently unrelated processes, such as cell proliferation, apoptosis, DNA-repair, transcriptional control, ribosome biogenesis and cell migration. Most of the interactions of HDGF with diverse molecules has been assigned to the hath region of HDGF. In this study we describe two previously unknown HDGF isoforms, HDGF-B and HDGF-C, generated via alternative splicing with structurally unrelated N-terminal regions of their hath region, which is clearly different from the well described isoform, HDGF-A. In silico modeling revealed striking differences near the PHWP motif, an essential part of the binding site for glycosaminoglycans and DNA/RNA. This observation prompted the hypothesis that these isoforms would have distinct interaction patterns with correspondingly diverse roles on cellular processes. Indeed, we discovered specific associations of HDGF-B and HDGF-C with cytoskeleton elements, such as tubulin and dynein, suggesting previously unknown functions of HDGF in retrograde transport, site directed localization and/or cytoskeleton organization. In contrast, the main isoform HDGF-A does not interact directly with the cytoskeleton, but via RNA with messenger ribonucleoprotein (mRNP) complexes. In summary, the discovery of HDGF splice variants with their discrete binding activities and subcellular distributions opened new avenues for understanding its biological function and importance.


2011 ◽  
Vol 47 (2) ◽  
pp. 324-332 ◽  
Author(s):  
Holly V. Moeller ◽  
Matthew D. Johnson ◽  
Paul G. Falkowski

2019 ◽  
Vol 20 (11) ◽  
pp. 2730 ◽  
Author(s):  
Chunlai Wu ◽  
Xupo Ding ◽  
Zehong Ding ◽  
Weiwei Tie ◽  
Yan Yan ◽  
...  

The class III peroxidase (POD) enzymes participate in plant development, hormone signaling, and stress responses. However, little is known about the POD family in cassava. Here, we identified 91 cassava POD genes (MePODs) and classified them into six subgroups using phylogenetic analysis. Conserved motif analysis demonstrated that all MePOD proteins have typical peroxidase domains, and gene structure analysis showed that MePOD genes have between one and nine exons. Duplication pattern analysis suggests that tandem duplication has played a role in MePOD gene expansion. Comprehensive transcriptomic analysis revealed that MePOD genes in cassava are involved in the drought response and postharvest physiological deterioration. Several MePODs underwent transcriptional changes after various stresses and related signaling treatments were applied. In sum, we characterized the POD family in cassava and uncovered the transcriptional control of POD genes in response to various stresses and postharvest physiological deterioration conditions. These results can be used to identify potential target genes for improving the stress tolerance of cassava crops.


2010 ◽  
Vol 30 (21) ◽  
pp. 5071-5085 ◽  
Author(s):  
Helen Yu ◽  
Nazar Mashtalir ◽  
Salima Daou ◽  
Ian Hammond-Martel ◽  
Julie Ross ◽  
...  

ABSTRACT The candidate tumor suppressor BAP1 is a deubiquitinating enzyme (DUB) involved in the regulation of cell proliferation, although the molecular mechanisms governing its function remain poorly defined. BAP1 was recently shown to interact with and deubiquitinate the transcriptional regulator host cell factor 1 (HCF-1). Here we show that BAP1 assembles multiprotein complexes containing numerous transcription factors and cofactors, including HCF-1 and the transcription factor Yin Yang 1 (YY1). Through its coiled-coil motif, BAP1 directly interacts with the zinc fingers of YY1. Moreover, HCF-1 interacts with the middle region of YY1 encompassing the glycine-lysine-rich domain and is essential for the formation of a ternary complex with YY1 and BAP1 in vivo. BAP1 activates transcription in an enzymatic-activity-dependent manner and regulates the expression of a variety of genes involved in numerous cellular processes. We further show that BAP1 and HCF-1 are recruited by YY1 to the promoter of the cox7c gene, which encodes a mitochondrial protein used here as a model of BAP1-activated gene expression. Our findings (i) establish a direct link between BAP1 and the transcriptional control of genes regulating cell growth and proliferation and (ii) shed light on a novel mechanism of transcription regulation involving ubiquitin signaling.


2019 ◽  
Author(s):  
Neetu Saini ◽  
Apurva Sarin

AbstractThe assembly of signaling hierarchies and their spatiotemporal organization together, contribute to diverse signaling outcomes. This is evident in the Notch pathway, which regulates an array of cellular processes, despite a small number of core components. Here, we describe a Notch4 activated signaling cascade, dependent on the nucleolar localization of the Notch4 Intracellular Domain (NIC4), that protects cells from genotoxic damage. Localization was assessed by immune-staining for endogenous Notch4 and visualization by confocal microscopy, in breast cancer cell lines. Live-cell, imaging-based, biophysical analysis of NIC4-GFP expressing cells, indicated unhindered mobility between the nucleolus and nucleoplasm and a stable nucleolar pool of NIC4-GFP. RNAi-mediated ablations, coupled with analysis of recombinant forms of NIC4 with modifications of its nucleolar localization sequence, confirmed nucleolar localization and identified the nucleolar proteins, Nucleolin and Fibrillarin, as key intermediates in the NIC4-activated signaling cascade. The transcriptional control of ribosome biogenesis (47s and 45s pre-rRNA transcription), emerged as another unexpected consequence of the subcellular distribution of NIC4. Taken together, this study describes intrinsic features of NIC4 that confer spatial flexibility and expand the repertoire of Notch4 signaling.


Author(s):  
Congcong Cao ◽  
Qian Ma ◽  
Shaomei Mo ◽  
Ge Shu ◽  
Qunlong Liu ◽  
...  

Androgen receptor (AR) signaling is essential for maintaining spermatogenesis and male fertility. However, the molecular mechanisms by which AR acts between male germ cells and somatic cells during spermatogenesis have not begun to be revealed until recently. With the advances obtained from the use of transgenic mice lacking AR in Sertoli cells (SCARKO) and single-cell transcriptomic sequencing (scRNA-seq), the cell specific targets of AR action as well as the genes and signaling pathways that are regulated by AR are being identified. In this study, we collected scRNA-seq data from wild-type (WT) and SCARKO mice testes at p20 and identified four somatic cell populations and two male germ cell populations. Further analysis identified that the distribution of Sertoli cells was completely different and uncovered the cellular heterogeneity and transcriptional changes between WT and SCARKO Sertoli cells. In addition, several differentially expressed genes (DEGs) in SCARKO Sertoli cells, many of which have been previously implicated in cell cycle, apoptosis and male infertility, have also been identified. Together, our research explores a novel perspective on the changes in the transcription level of various cell types between WT and SCARKO mice testes, providing new insights for the investigations of the molecular and cellular processes regulated by AR signaling in Sertoli cells.


2020 ◽  
Vol 22 ◽  
Author(s):  
Asimul Islam ◽  
Anas Shamsi ◽  
Rashid Waseem ◽  
Syed Kazim

Abstract:: In the last few years, a massive increase in the research has been observed that focusses on investigating the role of mitochondria in pathogenesis of several neurodegenerative disorders. Mitochondria are vital cell organelles having im-portant roles in different cellular processes including energy production, calcium signaling, ROS generation, apoptosis, etc. Therefore, healthy mitochondria are necessary for cell survival and functioning. It would seem feasible that mitochondrial dysfunction will have implications in various pathological conditions. A large body of evidence indicates the role of mito-chondrion as a potential key player in the loss or dysfunction of neurons in various neurodegenerative disorders. In this review, we provide an insight into the mitochondrial dysfunction and its involvement in the pathology of several neurolog-ical diseases such as Alzheimer’s disease, Parkinson’s disease, Amyotrophic Lateral Sclerosis, Hypoxic-Ischemic Brain Injury and many more.


Sign in / Sign up

Export Citation Format

Share Document