scholarly journals Global View on the Cytokinin Regulatory System in Potato

2020 ◽  
Vol 11 ◽  
Author(s):  
Sergey N. Lomin ◽  
Yulia A. Myakushina ◽  
Oksana O. Kolachevskaya ◽  
Irina A. Getman ◽  
Ekaterina M. Savelieva ◽  
...  

Cytokinins (CKs) were earlier shown to promote potato tuberization. Our study aimed to identify and characterize CK-related genes which constitute CK regulatory system in the core potato (Solanum tuberosum) genome. For that, CK-related genes were retrieved from the sequenced genome of the S. tuberosum doubled monoploid (DM) Phureja group, classified and compared with Arabidopsis orthologs. Analysis of selected gene expression was performed with a transcriptome database for the S. tuberosum heterozygous diploid line RH89-039-16. Genes responsible for CK signaling, biosynthesis, transport, and metabolism were categorized in an organ-specific fashion. According to this database, CK receptors StHK2/3 predominate in leaves and flowers, StHK4 in roots. Among phosphotransmitters, StHP1a expression largely predominates. Surprisingly, two pseudo-phosphotransmitters intended to suppress CK effects are hardly expressed in studied organs. Among B-type RR genes, StRR1b, StRR11, and StRR18a are actively expressed, with StRR1b expressing most uniformly in all organs and StRR11 exhibiting the highest expression in roots. By cluster analysis four types of prevailing CK-signaling chains were identified in (1) leaves and flowers, StHK2/3→StHP1a→StRR1b/+; (2) shoot apical meristems, stolons, and mature tubers, StHK2/4→StHP1a→StRR1b/+; (3) stems and young tubers, StHK2/4→StHP1a→StRR1b/11/18a; and (4) roots and tuber sprouts, StHK4→StHP1a→StRR11/18a. CK synthesis genes StIPT3/5 and StCYP735A are expressed mainly in roots followed by tuber sprouts, but rather weakly in stolons and tubers. By contrast, CK-activation genes StLOGs are active in stolons, and StLOG3b expression is even stolon-confined. Apparently, the main CK effects on tuber initiation are realized via activity of StLOG1/3a/3b/7c/8a genes in stolons. Current advances and future directions in potato research are discussed.

Cells ◽  
2020 ◽  
Vol 9 (7) ◽  
pp. 1675 ◽  
Author(s):  
Oleg V. Bylino ◽  
Airat N. Ibragimov ◽  
Yulii V. Shidlovskii

The genomes of all organisms abound with various cis-regulatory elements, which control gene activity. Transcriptional enhancers are a key group of such elements in eukaryotes and are DNA regions that form physical contacts with gene promoters and precisely orchestrate gene expression programs. Here, we follow gradual evolution of this regulatory system and discuss its features in different organisms. In eubacteria, an enhancer-like element is often a single regulatory element, is usually proximal to the core promoter, and is occupied by one or a few activators. Activation of gene expression in archaea is accompanied by the recruitment of an activator to several enhancer-like sites in the upstream promoter region. In eukaryotes, activation of expression is accompanied by the recruitment of activators to multiple enhancers, which may be distant from the core promoter, and the activators act through coactivators. The role of the general DNA architecture in transcription control increases in evolution. As a whole, it can be seen that enhancers of multicellular eukaryotes evolved from the corresponding prototypic enhancer-like regulatory elements with the gradually increasing genome size of organisms.


2021 ◽  
Vol 12 ◽  
Author(s):  
Hugh G. Nimmo ◽  
Janet Laird

The core of the plant circadian clock involves multiple interlocking gene expression loops and post-translational controls along with inputs from light and metabolism. The complexity of the interactions is such that few specific functions can be ascribed to single components. In previous work, we reported differences in the operation of the clocks in Arabidopsis shoots and roots, including the effects of mutations of key clock components. Here, we have used luciferase imaging to study prr7 mutants expressing CCA1::LUC and GI::LUC markers. In mature shoots expressing CCA1::LUC, loss of PRR7 radically altered behaviour in light:dark cycles and caused loss of rhythmicity in constant light but had little effect on roots. In contrast, in mature plants expressing GI::LUC, loss of PRR7 had little effect in light:dark cycles but in constant light increased the circadian period in shoots and reduced it in roots. We conclude that most or all of the circadian input to the CCA1 promoter in shoots is mediated by PRR7 and that loss of PRR7 has organ-specific effects. The results emphasise the differences in operation of the shoot and root clocks, and the importance of studying clock mutants in both light:dark cycles and constant light.


2021 ◽  
Author(s):  
jintao cao ◽  
SHUAI SUN ◽  
RAN LI ◽  
RUI MIN ◽  
XINGYU FAN ◽  
...  

Abstract Background The current epidemiology shows that the incidence of breast cancer is increasing year by year and tends to be younger. Triple-negative breast cancer is the most malignant of breast cancer subtypes. The application of bioinformatics in tumor research is becoming more and more extensive. This study provided research ideas and basis for exploring the potential targets of gene therapy for triple-negative breast cancer (TNBC). Methods We analyzed three gene expression profiles (GSE64790、GSE62931、GSE38959) selected from the Gene Expression Omnibus (GEO) database. The GEO2R online analysis tool was used to screen for differentially expressed genes (DEGs) between TNBC and normal tissues. Gene Ontology (GO) function and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis were applied to identify the pathways and functional annotation of DEGs. Protein–protein interaction network of these DEGs were visualized by the Metascape gene-list analysis tool so that we could find the protein complex containing the core genes. Subsequently, we investigated the transcriptional data of the core genes in patients with breast cancer from the Oncomine database. Moreover, the online Kaplan–Meier plotter survival analysis tool was used to evaluate the prognostic value of core genes expression in TNBC patients. Finally, immunohistochemistry (IHC) was used to evaluated the expression level and subcellular localization of CCNB2 on TNBC tissues. Results A total of 66 DEGs were identified, including 33 up-regulated genes and 33 down-regulated genes. Among them, a potential protein complex containing five core genes was screened out. The high expression of these core genes was correlated to the poor prognosis of patients suffering breast cancer, especially the overexpression of CCNB2. CCNB2 protein positively expressed in the cytoplasm, and its expression in triple-negative breast cancer tissues was significantly higher than that in adjacent tissues. Conclusions CCNB2 may play a crucial role in the development of TNBC and has the potential as a prognostic biomarker of TNBC.


2018 ◽  
Vol 37 ◽  
pp. 92-96 ◽  
Author(s):  
Chan-Hee Kim ◽  
Hye-Jin Go ◽  
Hye Young Oh ◽  
Yong Hun Jo ◽  
Maurice R. Elphick ◽  
...  

Cells ◽  
2020 ◽  
Vol 9 (5) ◽  
pp. 1167
Author(s):  
Manjinder S. Cheema ◽  
Katrina V. Good ◽  
Bohyun Kim ◽  
Heddy Soufari ◽  
Connor O’Sullivan ◽  
...  

The replication independent (RI) histone H2A.Z is one of the more extensively studied variant members of the core histone H2A family, which consists of many replication dependent (RD) members. The protein has been shown to be indispensable for survival, and involved in multiple roles from DNA damage to chromosome segregation, replication, and transcription. However, its functional involvement in gene expression is controversial. Moreover, the variant in several groups of metazoan organisms consists of two main isoforms (H2A.Z-1 and H2A.Z-2) that differ in a few (3–6) amino acids. They comprise the main topic of this review, starting from the events that led to their identification, what is currently known about them, followed by further experimental, structural, and functional insight into their roles. Despite their structural differences, a direct correlation to their functional variability remains enigmatic. As all of this is being elucidated, it appears that a strong functional involvement of isoform variability may be connected to development.


2021 ◽  
Author(s):  
Sarah E. Fritz ◽  
Soumya Ranganathan ◽  
J. Robert Hogg

AbstractThe nonsense-mediated mRNA decay (NMD) pathway monitors translation termination to degrade transcripts with premature stop codons and regulate thousands of human genes. Due to the major role of NMD in RNA quality control and gene expression regulation, it is important to understand how the pathway responds to changing cellular conditions. Here we show that an alternative mammalian-specific isoform of the core NMD factor UPF1, termed UPF1LL, enables condition-dependent remodeling of NMD specificity. UPF1LL associates more stably with potential NMD target mRNAs than the major UPF1SL isoform, expanding the scope of NMD to include many transcripts normally immune to the pathway. Unexpectedly, the enhanced persistence of UPF1LL on mRNAs supports induction of NMD in response to rare translation termination events. Thus, while canonical NMD is abolished by translational repression, UPF1LL activity is enhanced, providing a mechanism to rapidly rewire NMD specificity in response to cellular stress.


2021 ◽  
Author(s):  
Ricardo N Ramirez ◽  
Kaitavjeet Chowdhary ◽  
Juliette Leon ◽  
Diane Mathis ◽  
Christophe Benoist

Gene expression programs are specified by higher-order chromatin structure and enhancer-promoter loops (EPL). T regulatory cells (Treg) identity is dominantly specified by the transcription factor FoxP3, whose mechanism of action is unclear. We applied proximity-ligation with chromatin immunoprecipitation (HiChIP) in Treg and closely related conventional CD4+ T cells (Tconv). EPL identified by H3K27Ac HiChIP showed a range of connection intensity, with some super-connected genes. TF-specific HiChIP showed that FoxP3 interacts with EPLs at a large number of genes, including some not differentially expressed in Treg vs Tconv, but enriched at the core Treg signature loci that it upregulates. FoxP3 association correlates with heightened H3H27Ac looping, as ascertained by analysis of FoxP3-deficient Treg-like cells. There was marked asymmetry in the loci where FoxP3 associated at the enhancer- or the promoter-side of EPLs, with enrichment for different transcriptional cofactors. FoxP3 EPL intensity distinguished gene clusters identified by single-cell ATAC-seq as co-varying between individual Tregs, supporting a direct transactivation model for FoxP3 in determining Treg identity.


2021 ◽  
pp. mbc.E20-10-0645
Author(s):  
James P. Kemp ◽  
Xiao-Cui Yang ◽  
Zbigniew Dominski ◽  
William F. Marzluff ◽  
Robert J. Duronio

The Histone Locus Body (HLB) is an evolutionarily conserved nuclear body that regulates the transcription and processing of replication-dependent (RD) histone mRNAs, which are the only eukaryotic mRNAs lacking a poly-A tail. Many nuclear bodies contain distinct domains, but how internal organization is related to nuclear body function is not fully understood. Here, we demonstrate using structured illumination microscopy that Drosophila HLBs have a “core-shell” organization in which the internal core contains transcriptionally active RD histone genes. The N-terminus of Mxc, which contains a domain required for Mxc oligomerization, HLB assembly, and RD histone gene expression, is enriched in the HLB core. In contrast, the C-terminus of Mxc is enriched in the HLB outer shell as is FLASH, a component of the active U7 snRNP that co-transcriptionally cleaves RD histone pre-mRNA. Consistent with these results, we show biochemically that FLASH binds directly to the Mxc C-terminal region. In the rapid S-M nuclear cycles of syncytial blastoderm Drosophila embryos, the HLB disassembles at mitosis and reassembles the core-shell arrangement as histone gene transcription is activated immediately after mitosis. Thus, the core-shell organization is coupled to zygotic histone gene transcription, revealing a link between HLB internal organization and RD histone gene expression.


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