Multi-analysis of sheath senescence provides new insights into bamboo shoot development at the fast growth stage

2020 ◽  
Author(s):  
Ming Chen ◽  
Ye Ju ◽  
Zishan Ahmad ◽  
Zengfang Yin ◽  
Ding Yulong ◽  
...  

Abstract Sheath senescence is an important part of bamboo shoot development during the fast growth stage. However, no information has been reported about this distinctive process until now. Using multiple approaches, we found that sheath senescence is a complex process that occurs sequentially with chloroplast corruption, chlorophyll degradation, and water loss. Reactive oxygen species (ROS), salicylic acid, and abscisic acid also accumulate in the senescing sheath. Transcriptome analysis showed that NAC and WRKY transcription factors, such as NAC2 and WRKY75, as well as their possible downstream target genes, such as those involved in ROS production, proteolysis, and nutrition recycling, constitute the gene network of the bamboo sheath senescence process. Furthermore, the initiation of sheath senescence might be triggered by hexokinase genes, such as HXK6, which is localized to the mitochondrion and could promote leaf senescence when overexpressed in Arabidopsis. Sheath senescence occurs after the growth decrease of the internodes, which provides assimilates. The slowing of internode growth possibly results in sugar accumulation, such as glucose, in the sheath, which finally upregulates hexokinase genes and initiates sheath senescence. These findings reveal that sheath senescence is a multilevel regulation process and has a close link to the corresponding internode growth, which provides new insights into the shoot development of bamboo during the fast growth stage.

2020 ◽  
Author(s):  
Ming Chen ◽  
Ye Ju ◽  
Zishan Ahmad ◽  
Zengfang Yin ◽  
Yulong Ding ◽  
...  

Abstract Sheath senescence is an important part of bamboo shoot development during the fast growth stage. However, no information has been reported about this distinctive process until now. Using multiple approaches, we found that sheath senescence is a complex process that occurs sequentially with chloroplast corruption, chlorophyll degradation and water loss. Reactive oxygen species (ROS), salicylic acid and abscisic acid also accumulate in the senescing sheath. Transcriptome analysis showed that NAC and WRKY transcription factors, such as NAC2 and WRKY75, as well as their possible downstream target genes, such as those involved in ROS production, proteolysis and nutrition recycling, constitute the gene network of the bamboo sheath senescence process. Furthermore, the initiation of sheath senescence might be triggered by hexokinase genes, such as HXK6, which is localized to the mitochondrion and could promote leaf senescence when overexpressed in Arabidopsis. Sheath senescence occurs after the growth decrease of the internodes, which provides assimilates. The slowing of internode growth possibly results in sugar accumulation, such as glucose, in the sheath, which finally upregulates hexokinase genes and initiates sheath senescence. These findings reveal that sheath senescence is a multilevel regulation process and has a close link to the corresponding internode growth, which provides new insights into the shoot development of bamboo during the fast growth stage.


Genetics ◽  
2003 ◽  
Vol 164 (1) ◽  
pp. 247-258 ◽  
Author(s):  
Jinghong Li ◽  
Willis X Li

Abstract Overactivation of receptor tyrosine kinases (RTKs) has been linked to tumorigenesis. To understand how a hyperactivated RTK functions differently from wild-type RTK, we conducted a genome-wide systematic survey for genes that are required for signaling by a gain-of-function mutant Drosophila RTK Torso (Tor). We screened chromosomal deficiencies for suppression of a gain-of-function mutation tor (torGOF), which led to the identification of 26 genomic regions that, when in half dosage, suppressed the defects caused by torGOF. Testing of candidate genes in these regions revealed many genes known to be involved in Tor signaling (such as those encoding the Ras-MAPK cassette, adaptor and structural molecules of RTK signaling, and downstream target genes of Tor), confirming the specificity of this genetic screen. Importantly, this screen also identified components of the TGFβ (Dpp) and JAK/STAT pathways as being required for TorGOF signaling. Specifically, we found that reducing the dosage of thickveins (tkv), Mothers against dpp (Mad), or STAT92E (aka marelle), respectively, suppressed torGOF phenotypes. Furthermore, we demonstrate that in torGOF embryos, dpp is ectopically expressed and thus may contribute to the patterning defects. These results demonstrate an essential requirement of noncanonical signaling pathways for a persistently activated RTK to cause pathological defects in an organism.


2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Aileen Patricia Szczepanski ◽  
Lu Wang

AbstractHistone H2AK119 mono-ubiquitination (H2AK119Ub) is a relatively abundant histone modification, mainly catalyzed by the Polycomb Repressive Complex 1 (PRC1) to regulate Polycomb-mediated transcriptional repression of downstream target genes. Consequently, H2AK119Ub can also be dynamically reversed by the BAP1 complex, an evolutionarily conserved multiprotein complex that functions as a general transcriptional activator. In previous studies, it has been reported that the BAP1 complex consists of important biological roles in development, metabolism, and cancer. However, identifying the BAP1 complex’s regulatory mechanisms remains to be elucidated due to its various complex forms and its ability to target non-histone substrates. In this review, we will summarize recent findings that have contributed to the diverse functional role of the BAP1 complex and further discuss the potential in targeting BAP1 for therapeutic use.


2020 ◽  
Vol 22 (Supplement_3) ◽  
pp. iii414-iii414
Author(s):  
Muh-Lii Liang ◽  
Tsung-Han Hsieh ◽  
Tai-Tong Wong

Abstract BACKGROUND Glial-lineage tumors constitute a heterogeneous group of neoplasms, comprising gliomas, oligodendrogliomas, and ependymomas, which account for 40%–50% of all pediatric central nervous system tumors. Advances in modern neuro-oncological therapeutics are aimed at improving neoadjuvant chemotherapy and deferring radiotherapy because radiation exposure may cause long-term side effects on the developing brain in young children. Despite aggressive treatment, more than half the high-grade gliomas (pHGGs) and one-third of ependymomas exhibit recurrence within 2 years of initial treatment. METHODS By using integrated bioinformatics and through experimental validation, we found that at least one gene among CCND1, CDK4, and CDK6 was overexpressed in pHGGs and ependymomas. RESULTS The use of abemaciclib, a highly selective CDK4/6 inhibitor, effectively inhibited cell proliferation and reduced the expression of cell cycle–related and DNA repair–related gene expression, which was determined through RNA-seq analysis. The efficiency of abemaciclib was validated in vitro in pHGGs and ependymoma cells and in vivo by using subcutaneously implanted ependymoma cells from patient-derived xenograft (PDX) in mouse models. Abemaciclib demonstrated the suppression of RB phosphorylation, downstream target genes of E2F, G2M checkpoint, and DNA repair, resulting in tumor suppression. CONCLUSION Abemaciclib showed encouraging results in preclinical pediatric glial-lineage tumors models and represented a potential therapeutic strategy for treating challenging tumors in children.


2021 ◽  
Vol 6 (1) ◽  
Author(s):  
Xiulin Jiang ◽  
Baiyang Liu ◽  
Zhi Nie ◽  
Lincan Duan ◽  
Qiuxia Xiong ◽  
...  

AbstractN6-methyladenosine (m6A) is the most prevalent, abundant and conserved internal cotranscriptional modification in eukaryotic RNAs, especially within higher eukaryotic cells. m6A modification is modified by the m6A methyltransferases, or writers, such as METTL3/14/16, RBM15/15B, ZC3H3, VIRMA, CBLL1, WTAP, and KIAA1429, and, removed by the demethylases, or erasers, including FTO and ALKBH5. It is recognized by m6A-binding proteins YTHDF1/2/3, YTHDC1/2 IGF2BP1/2/3 and HNRNPA2B1, also known as “readers”. Recent studies have shown that m6A RNA modification plays essential role in both physiological and pathological conditions, especially in the initiation and progression of different types of human cancers. In this review, we discuss how m6A RNA methylation influences both the physiological and pathological progressions of hematopoietic, central nervous and reproductive systems. We will mainly focus on recent progress in identifying the biological functions and the underlying molecular mechanisms of m6A RNA methylation, its regulators and downstream target genes, during cancer progression in above systems. We propose that m6A RNA methylation process offer potential targets for cancer therapy in the future.


2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Masaharu Yoshihara ◽  
Teppei Nishino ◽  
Manoj Kumar Yadav ◽  
Akihiro Kuno ◽  
Takeshi Nagata ◽  
...  

Abstract Objective The Delta-Notch signaling pathway induces fine-grained patterns of differentiation from initially homogeneous progenitor cells in many biological contexts, including Drosophila bristle formation, where mathematical modeling reportedly suggests the importance of production rate of the components of this signaling pathway. In contrast, the epithelial differentiation of bile ducts in the developing liver is unique in that it occurs around the portal vein cells, which express extremely high amounts of Delta ligands and act as a disturbance for the amount of Delta ligands in the field by affecting the expression levels of downstream target genes in the cells nearby. In the present study, we mathematically examined the dynamics of the Delta-Notch signaling pathway components in disturbance-driven biliary differentiation, using the model for fine-grained patterns of differentiation. Results A portal vein cell induced a high Notch signal in its neighboring cells, which corresponded to epithelial differentiation, depending on the production rates of Delta ligands and Notch receptors. In addition, this epithelial differentiation tended to occur in conditions where fine-grained patterning was reported to be lacking. These results highlighted the potential importance of the stability towards homogeneity determined by the production rates in Delta ligands and Notch receptors, in a disturbance-dependent epithelial differentiation.


Development ◽  
1994 ◽  
Vol 120 (8) ◽  
pp. 2287-2296 ◽  
Author(s):  
P. de Zulueta ◽  
E. Alexandre ◽  
B. Jacq ◽  
S. Kerridge

Homeotic genes determine the identities of metameres in Drosophila. We have examined functional aspects of the homeotic gene teashirt by ectopically expressing its product under the control of a heat-shock promoter during embryogenesis. Our results confirm that the gene is critical for segmental identity of the larva. Under mild heat-shock conditions, the Teashirt protein induces an almost complete transformation of the labial to prothoracic segmental identity, when expressed before 8 hours of development. Positive autoregulation of the endogenous teashirt gene and the presence of Sex combs reduced protein in the labium explain this homeosis. Patterns in the maxillary and a more anterior head segment are partly replaced with trunk ones. Additional Teashirt protein has no effect on the identity of the trunk segments where the gene is normally expressed; teashirt function is overridden by some homeotic complex acting in the posterior trunk. Strong heat-shock regimes provoke novel defects: ectopic sense organs differentiate in posterior abdominal segments and trunk pattern elements differentiate in the ninth abdominal segment. Teashirt acts in a partially redundant way with certain homeotic complex proteins but co-operates with them for the establishment of specific segment types. We suggest that Teashirt and HOM-C proteins regulate common sets of downstream target genes.


Development ◽  
1996 ◽  
Vol 122 (5) ◽  
pp. 1373-1383 ◽  
Author(s):  
S. Christensen ◽  
V. Kodoyianni ◽  
M. Bosenberg ◽  
L. Friedman ◽  
J. Kimble

The homologous receptors LIN-12 and GLP-1 mediate diverse cell-signaling events during development of the nematode Caenorhabditis elegans. These two receptors appear to be functionally interchangeable and have sequence similarity to Drosophila Notch. Here we focus on a molecular analysis of the lag-1 gene (lin-12 -and glp-1), which plays a central role in LIN-12 and GLP-1-mediated signal transduction. We find that the predicted LAG-1 protein is homologous to two DNA-binding proteins: human C Promoter Binding Factor (CBF1) and Drosophila Suppressor of Hairless (Su(H)). Furthermore, we show that LAG-1 binds specifically to the DNA sequence RTGGGAA, previously identified as a CBF-1/Su(H)-binding site. Finally, we report that the 5′ flanking regions and first introns of the lin-12, glp-1 and lag-1 genes are enriched for potential LAG-1-binding sites. We propose that LAG-1 is a transcriptional regulator that serves as a primary link between the LIN-12 and GLP-1 receptors and downstream target genes in C. elegans. In addition, we propose that LAG-1 may be a key component of a positive feedback loop that amplifies activity of the LIN-12/GLP-1 pathway.


2021 ◽  
Vol 17 (10) ◽  
pp. 1960-1971
Author(s):  
Sheng Huang ◽  
Changye Zou ◽  
Shangyan Xie ◽  
Bin Wang ◽  
Xitao LingHu ◽  
...  

Bone metastasis is a significant cause of morbidity and mortality in patients with prostate cancer (PCa). This study is aimed at illustrating the mechanism of sweroside-mediated regulation in bone metastasis in PCa cells. Owing to the limitations of antitumor drugs in terms of their physical and chemical properties, making them into nanomaterials can effectively improve drug stability and bioavailability. Apoptosis was assessed with flow cytometry using the annexin V/propidium iodide binding assay; proteins, including p53, P21, Bcl-2, and Bax; and induction of intracellular reactive oxygen species (ROS). Using colony formation assay, sphere formation assay, and the expression changes in CD133 and CD44, stem cell characteristics were assessed. Epithelial–mesenchymal transition (EMT) activity was accessed by levels of the expression changes of EMT-related markers, vimentin and E-cadherin. Wnt/β-catenin signaling pathway was examined to detect the levels of the expression changes of snail and β-catenin. PC-3 cells were treated with lithium chloride (LiCl), which is an agonist of Wnt/β-catenin signaling, and the levels of CD133, CD44, vimentin, E-cadherin, snail, and β-catenin were detected. T-cell factor/lymphocyte enhancer factor (TCF/LEF) activity in cells overexpressing β-catenin was used to detect the effects on β-catenin transcription, and the expression of c-myc, Cyclin D1, Survivin, and MMP-7 were used to detect Wnt downstream target genes. Our results suggest that sweroside induces apoptosis and intracellular ROS; upregulates apoptotic proteins; and suppresses proliferation, invasion, and migration, preventing stem cell characteristics, including sphere formation, colony formation, and CD133 and CD44 expressions. Furthermore, sweroside nanoparticles exerts inhibitory effects on β-catenin transcription by suppressing TTCF/LEF activity in cells overexpressing β-catenin and downregulation of the expression of Wnt downstream target genes, including c-myc, Cyclin D1, Survivin, and MMP-7. The potential therapeutic effect of sweroside nanoparticles on bone metastatis of PCa was suggested, by these findings.


2018 ◽  
Vol 122 (5) ◽  
pp. 518-526 ◽  
Author(s):  
He Zhang ◽  
Jun Guo ◽  
Liping Mao ◽  
Qianqian Li ◽  
Mengnan Guo ◽  
...  

AbstractAs important epigenetic regulators, microRNA regulate protein expression by triggering the degradation of target mRNA and/or by inhibiting their translation. Dysregulation of microRNA expression has been reported in several cancers, including colorectal cancer. In this study, microRNA-array differential analysis revealed strongly enhanced expression of miR-24-1-5p in the colon tissue of azoxymethane/dextran sulphate sodium-induced mice that were fed with black raspberry anthocyanins for 9 weeks. Overexpression of miR-24-1-5p in human colorectal cancer cells significantly repressed β-catenin expression, and simultaneously decreased cell proliferation, migration and survival. Furthermore, miR-24-1-5p could target β-catenin and trigger a negative regulatory loop for β-catenin and its downstream target genes. β-Catenin signalling is vital to the formation and progression of human colorectal cancer. The current findings therefore identified miR-24-1-5p as a potent regulator of β-catenin, and this may provide a novel chemopreventive and therapeutic strategy for β-catenin signalling-driven colorectal cancer.


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