The spatial organization of the genome plays an important role in the regulation of gene expression. How- ever, the core structural features of animal genomes, such as topologically associated ...domains （TADs） and chromatin loops, are not prominent in the extremely compact Arabidopsis genome. In this study, we examine the chromatin architecture, as well as their DNA methylation, histone modifications, accessible chromatin, and gene expression, of maize, tomato, sorghum, foxtail millet, and rice with genome sizes ranging from 0.4 to 2.4 Gb. We found that these plant genomes can be divided into mammalian-like A/B compartments. At higher resolution, the chromosomes of these plants can be further partitioned to local AJB compartments that reflect their euchromatin, heterochromatin, and polycomb status. Chromatins in all these plants are organized into domains that are not conserved across species. They show similarity to the Drosophila compartment domains, and are clustered into active, polycomb, repressive, and interme- diate types based on their transcriptional activities and epigenetic signatures, with domain border overlaps with the local A/B compartment junctions. In the large maize and tomato genomes, we observed extensive chromatin loops. However, unlike the mammalian chromatin loops that are enriched at the TAD border, plant chromatin loops are often formed between gene islands outside the repressive domains and are closely associated with active compartments. Our study indicates that plants have complex and unique 3D chromatin architectures, which require further study to elucidate their biological functions.
In plants, the basic helix-loop-helix (bHLH) transcription factors play key roles in diverse biological processes. Genome-wide comprehensive and systematic analyses of bHLH proteins have been well ...conducted in Arabidopsis, rice, tomato and other plant species. However, only few of bHLH family genes have been functional characterized in maize.
In this study, our genome-wide analysis identified 208 putative bHLH family proteins (ZmbHLH proteins) in maize (Zea mays). We classified these proteins into 18 subfamilies by comparing the ZmbHLHs with Arabidopsis thaliana bHLH proteins. Phylogenetic analysis, conserved protein motifs, and exon-intron patterns further supported the evolutionary relationships among these bHLH proteins. Genome distribution analysis found that the 208 ZmbHLH loci were located non-randomly on the ten maize chromosomes. Further, analysis of conserved cis-elements in the promoter regions, protein interaction networks, and expression patterns in roots, leaves, and seeds across developmental stages, suggested that bHLH family proteins in maize are probably involved in multiple physiological processes in plant growth and development.
We performed a genome-wide, systematic analysis of bHLH proteins in maize. This comprehensive analysis provides a useful resource that enables further investigation of the physiological roles and molecular functions of the ZmbHLH transcription factors.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
The transcription regulatory network inside a eukaryotic cell is defined by the combinatorial actions of transcription factors (TFs). However, TF binding studies in plants are too few in number to ...produce a general picture of this complex network. In this study, we use large-scale ChIP-seq to reconstruct it in the maize leaf, and train machine-learning models to predict TF binding and co-localization. The resulting network covers 77% of the expressed genes, and shows a scale-free topology and functional modularity like a real-world network. TF binding sequence preferences are conserved within family, while co-binding could be key for their binding specificity. Cross-species comparison shows that core network nodes at the top of the transmission of information being more conserved than those at the bottom. This study reveals the complex and redundant nature of the plant transcription regulatory network, and sheds light on its architecture, organizing principle and evolutionary trajectory.
The primary determinant of crop yield is photosynthetic capacity, which is under the control of photosynthesis-related genes. Therefore, the mining of genes involved in photosynthesis is important ...for the study of photosynthesis. MapMan Mercator 4 is a powerful annotation tool for assigning genes into proper functional categories; however, in maize, the functions of approximately 22.15% (9520) of genes remain unclear and are labeled "not assigned", which may include photosynthesis-related genes that have not yet been identified. The fast-increasing usage of the machine learning approach in solving biological problems provides us with a new chance to identify novel photosynthetic genes from functional "not assigned" genes in maize.
In this study, we proved the ensemble learning model using a voting eliminates the preferences of single machine learning models. Based on this evaluation, we implemented an ensemble based ML(Machine Learning) methods using a majority voting scheme and observed that including RNA-seq data from multiple photosynthetic mutants rather than only a single mutant could increase prediction accuracy. And we call this approach "A Machine Learning-based Photosynthetic-related Gene Detection approach (PGD)". Finally, we predicted 716 photosynthesis-related genes from the "not assigned" category of maize MapMan annotation. The protein localization prediction (TargetP) and expression trends of these genes from maize leaf sections indicated that the prediction was reliable and robust. And we put this approach online base on google colab.
This study reveals a new approach for mining novel genes related to a specific functional category and provides candidate genes for researchers to experimentally define their biological functions.
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Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Chromatins are not randomly packaged in the nucleus and their organization plays important roles in transcription regulation, which is best studied in the mammalian models. Using in situ Hi‐C, we ...have compared the 3D chromatin architectures of rice mesophyll and endosperm, foxtail millet bundle sheath and mesophyll, and maize bundle sheath, mesophyll and endosperm tissues. We found that their global A/B compartment partitions are stable across tissues, while local A/B compartment has tissue‐specific dynamic associated with differential gene expression. Plant domains are largely stable across tissues, while new domain border formations are often associated with transcriptional activation in the region. Genes inside plant domains are not conserved across species, and lack significant co‐expression behavior unlike those in mammalian TADs. Although we only observed chromatin loops between gene islands in the large genomes, the maize loop gene pairs’ syntenic orthologs have shorter physical distances in small genome monocots, suggesting that loops instead of domains might have conserved biological function. Our study showed that plants’ chromatin features might not have conserved biological functions as the mammalian ones.
RNA-seq technology has been widely adopted as an attractive alternative to microarray-based methods to study global gene expression. However, robust statistical tools to analyze these complex ...datasets are still lacking. By grouping genes with similar expression profiles across treatments, cluster analysis provides insight into gene functions and networks, and hence is an important technique for RNA-seq data analysis.
In this manuscript, we derive clustering algorithms based on appropriate probability models for RNA-seq data. An expectation-maximization algorithm and another two stochastic versions of expectation-maximization algorithms are described. In addition, a strategy for initialization based on likelihood is proposed to improve the clustering algorithms. Moreover, we present a model-based hybrid-hierarchical clustering method to generate a tree structure that allows visualization of relationships among clusters as well as flexibility of choosing the number of clusters. Results from both simulation studies and analysis of a maize RNA-seq dataset show that our proposed methods provide better clustering results than alternative methods such as the K-means algorithm and hierarchical clustering methods that are not based on probability models.
An R package, MBCluster.Seq, has been developed to implement our proposed algorithms. This R package provides fast computation and is publicly available at http://www.r-project.org
Broomcorn millet (Panicum miliaceum L.) has strong tolerance to abiotic stresses, and is probably one of the oldest crops, with its earliest cultivation that dated back to ca. ~10,000 years. We ...report here its genome assembly through a combination of PacBio sequencing, BioNano, and Hi-C (in vivo) mapping. The 18 super scaffolds cover ~95.6% of the estimated genome (~887.8 Mb). There are 63,671 protein-coding genes annotated in this tetraploid genome. About ~86.2% of the syntenic genes in foxtail millet have two homologous copies in broomcorn millet, indicating rare gene loss after tetraploidization in broomcorn millet. Phylogenetic analysis reveals that broomcorn millet and foxtail millet diverged around ~13.1 Million years ago (Mya), while the lineage specific tetraploidization of broomcorn millet may be happened within ~5.91 million years. The genome is not only beneficial for the genome assisted breeding of broomcorn millet, but also an important resource for other Panicum species.
Internal ribosome entry site (IRES)-driven translation is a common strategy among positive-sense, single-stranded RNA viruses for bypassing the host cell requirement of a 5' cap structure. In the ...current study, we identified the ribosomal protein L13 (RPL13) as a critical regulator of IRES-driven translation of foot-and-mouth disease virus (FMDV) but found that it is not essential for cellular global translation. RPL13 is also a determinant for translation and infection of Seneca Valley virus (SVV) and classical swine fever virus (CSFV), and this suggests that its function may also be conserved in unrelated IRES-containing viruses. We further showed that depletion of DEAD box helicase DDX3 disrupts binding of RPL13 to the FMDV IRES, whereas the reduction in RPL13 expression impairs the ability of DDX3 to promote IRES-driven translation directly. DDX3 cooperates with RPL13 to support the assembly of 80S ribosomes for optimal translation initiation of viral mRNA. Finally, we demonstrated that DDX3 affects the recruitment of the eukaryotic initiation factor eIF3 subunits e and j to the viral IRES. This work provides the first connection between DDX3 and eIF3e/j and recognition of the role of RPL13 in modulating viral IRES-dependent translation. This previously uncharacterized process may be involved in selective mRNA translation.
Accumulating evidence has unveiled the roles of ribosomal proteins (RPs) belonging to the large 60S subunit in regulating selective translation of specific mRNAs. The translation specificity of the large-subunit RPs in this process is thought provoking, given the role they play canonically in catalyzing peptide bond formation. Here, we have identified the ribosomal protein L13 (RPL13) as a critical regulator of IRES-driven translation during FMDV infection. Our study supports a model whereby the FMDV IRESs recruit helicase DDX3 recognizing RPL13 to facilitate IRES-driven translation, with the assistance of eIF3e and eIF3j. A better understanding of these specific interactions surrounding IRES-mediated translation initiation could have important implications for the selective translation of viral mRNA and thus for the development of effective prevention of viral infection.
We have analyzed the maize leaf transcriptome using Illumina sequencing. We mapped more than 120 million reads to define gene structure and alternative splicing events and to quantify transcript ...abundance along a leaf developmental gradient and in mature bundle sheath and mesophyll cells. We detected differential mRNA processing events for most maize genes. We found that 64% and 21% of genes were differentially expressed along the developmental gradient and between bundle sheath and mesophyll cells, respectively. We implemented Gbrowse, an electronic fluorescent pictograph browser, and created a two-cell biochemical pathway viewer to visualize datasets. Cluster analysis of the data revealed a dynamic transcriptome, with transcripts for primary cell wall and basic cellular metabolism at the leaf base transitioning to transcripts for secondary cell wall biosynthesis and C(4) photosynthetic development toward the tip. This dataset will serve as the foundation for a systems biology approach to the understanding of photosynthetic development.
Celotno besedilo
Dostopno za:
DOBA, IJS, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
Optical resonators are particularly suitable for anaemia state detection due to small sample size, real-time detection and low power consumption. However, the quality factor and sensitivity of ...resonant cavity sensors are mutually constrained, so the single objective optimization algorithms proposed so far can only achieve a single optimization of sensitivity or quality factor, which limits chip performance. This article presents a multi-objective optimization design of the runway ring resonant cavity sensor based on the BP-NSGA II algorithm, which has achieved good performance improvement. The simultaneous incorporation of quality factor and sensitivity provides access to key structural design parameters to overcome the limitations of sensitivity and quality factor constraints on each other, thereby improving sensor performance. The results show that the optimized structure has a sensitivity of
439 nm/RIU
, a quality factor of
938
, a relative error of
1.37%
and
3.9%
for the sensitivity and quality factor, respectively, a linearity of
0.00004636%
for the sensitivity, and a training time of
3
min. The method has the advantages of small errors and short learning time. A new optimization method is provided for the design of the resonant cavity of a runway ring.
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