Donkey genome and insight into the imprinting of fast karyotype evolution

Abstract The donkey, like the horse, is a promising model for exploring karyotypic instability. We report the de novo whole-genome assemblies of the donkey and the Asiatic wild ass. Our results reflect the distinct characteristics of donkeys, including more effective energy metabolism and better immunity than horses. The donkey shows a steady demographic trajectory. We detected abundant satellite sequences in some inactive centromere regions but not in neocentromere regions, while ribosomal RNAs frequently emerged in neocentromere regions but not in the obsolete centromere regions. Expanded miRNA families and five newly discovered miRNA target genes involved in meiosis may be associated with fast karyotype evolution. APC/C, controlling sister chromatid segregation, cytokinesis and the establishment of the G1 cell cycle phase were identified by analysis of miRNA targets and rapidly evolving genes.

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Nanopore sequencing and Hi-C scaffolding provide insight into the evolutionary dynamics of transposable elements and piRNA production in wild strains of Drosophila melanogaster

Nucleic Acids Research ◽

10.1093/nar/gkz1080 ◽

2019 ◽

Vol 48 (1) ◽

pp. 290-303 ◽

Cited By ~ 7

Author(s):

Christopher E Ellison ◽

Weihuan Cao

Keyword(s):

Drosophila Melanogaster ◽

Evolutionary Dynamics ◽

De Novo ◽

Population Level ◽

Chromosome Length ◽

Nanopore Sequencing ◽

Long Reads ◽

Wild Strains ◽

Genome Assemblies ◽

Insight Into

Abstract Illumina sequencing has allowed for population-level surveys of transposable element (TE) polymorphism via split alignment approaches, which has provided important insight into the population dynamics of TEs. However, such approaches are not able to identify insertions of uncharacterized TEs, nor can they assemble the full sequence of inserted elements. Here, we use nanopore sequencing and Hi-C scaffolding to produce de novo genome assemblies for two wild strains of Drosophila melanogaster from the Drosophila Genetic Reference Panel (DGRP). Ovarian piRNA populations and Illumina split-read TE insertion profiles have been previously produced for both strains. We find that nanopore sequencing with Hi-C scaffolding produces highly contiguous, chromosome-length scaffolds, and we identify hundreds of TE insertions that were missed by Illumina-based methods, including a novel micropia-like element that has recently invaded the DGRP population. We also find hundreds of piRNA-producing loci that are specific to each strain. Some of these loci are created by strain-specific TE insertions, while others appear to be epigenetically controlled. Our results suggest that Illumina approaches reveal only a portion of the repetitive sequence landscape of eukaryotic genomes and that population-level resequencing using long reads is likely to provide novel insight into the evolutionary dynamics of repetitive elements.

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Genomic Characterization Provides an Insight into the Pathogenicity of the Poplar Canker Bacterium Lonsdalea populi

Genes ◽

10.3390/genes12020246 ◽

2021 ◽

Vol 12 (2) ◽

pp. 246

Author(s):

Xiaomeng Chen ◽

Rui Li ◽

Yonglin Wang ◽

Aining Li

Keyword(s):

Genome Sequence ◽

Extracellular Enzymes ◽

De Novo ◽

Whole Genome Sequence ◽

Hybrid Poplars ◽

A Genome ◽

Conserved Genes ◽

Genomic Characterization ◽

Molecular Bases ◽

Insight Into

An emerging poplar canker caused by the gram-negative bacterium, Lonsdalea populi, has led to high mortality of hybrid poplars Populus × euramericana in China and Europe. The molecular bases of pathogenicity and bark adaptation of L. populi have become a focus of recent research. This study revealed the whole genome sequence and identified putative virulence factors of L. populi. A high-quality L. populi genome sequence was assembled de novo, with a genome size of 3,859,707 bp, containing approximately 3434 genes and 107 RNAs (75 tRNA, 22 rRNA, and 10 ncRNA). The L. populi genome contained 380 virulence-associated genes, mainly encoding for adhesion, extracellular enzymes, secretory systems, and two-component transduction systems. The genome had 110 carbohydrate-active enzyme (CAZy)-coding genes and putative secreted proteins. The antibiotic-resistance database annotation listed that L. populi was resistant to penicillin, fluoroquinolone, and kasugamycin. Analysis of comparative genomics found that L. populi exhibited the highest homology with the L. britannica genome and L. populi encompassed 1905 specific genes, 1769 dispensable genes, and 1381 conserved genes, suggesting high evolutionary diversity and genomic plasticity. Moreover, the pan genome analysis revealed that the N-5-1 genome is an open genome. These findings provide important resources for understanding the molecular basis of the pathogenicity and biology of L. populi and the poplar-bacterium interaction.

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Examination of the Transcriptional Response to LaMIR166a Overexpression in Larix kaempferi (Lamb.) Carr

Biology ◽

10.3390/biology10070576 ◽

2021 ◽

Vol 10 (7) ◽

pp. 576

Author(s):

Yanru Fan ◽

Wanfeng Li ◽

Zhexin Li ◽

Shaofei Dang ◽

Suying Han ◽

...

Keyword(s):

Cell Lines ◽

Molecular Mechanisms ◽

Target Genes ◽

De Novo ◽

Pearson Correlation ◽

Transcriptional Response ◽

Correlation Coefficients ◽

Embryonic Cell ◽

Larix Kaempferi ◽

Transgenic Cell

The study of somatic embryogenesis can provide insight into early plant development. We previously obtained LaMIR166a-overexpressing embryonic cell lines of Larix kaempferi (Lamb.) Carr. To further elucidate the molecular mechanisms associated with miR166 in this species, the transcriptional profiles of wild-type (WT) and three LaMIR166a-overexpressing transgenic cell lines were subjected to RNA sequencing using the Illumina NovaSeq 6000 system. In total, 203,256 unigenes were generated using Trinity de novo assembly, and 2467 differentially expressed genes were obtained by comparing transgenic and WT lines. In addition, we analyzed the cleaved degree of LaMIR166a target genes LaHDZ31–34 in different transgenic cell lines by detecting the expression pattern of LaHdZ31–34, and their cleaved degree in transgenic cell lines was higher than that in WT. The downstream genes of LaHDZ31–34 were identified using Pearson correlation coefficients. Yeast one-hybrid and dual-luciferase report assays revealed that the transcription factors LaHDZ31–34 could bind to the promoters of LaPAP, LaPP1, LaZFP5, and LaPHO1. This is the first report of gene expression changes caused by LaMIR166a overexpression in Japanese larch. These findings lay a foundation for future studies on the regulatory mechanism of miR166.

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Interspecies Chromosome Mapping in Caprimulgiformes, Piciformes, Suliformes, and Trogoniformes (Aves): Cytogenomic Insight into Microchromosome Organization and Karyotype Evolution in Birds

Cells ◽

10.3390/cells10040826 ◽

2021 ◽

Vol 10 (4) ◽

pp. 826

Author(s):

Rafael Kretschmer ◽

Marcelo Santos de Souza ◽

Ivanete de Oliveira Furo ◽

Michael N. Romanov ◽

Ricardo José Gunski ◽

...

Keyword(s):

Convergent Evolution ◽

Karyotype Evolution ◽

Rare Events ◽

Rare Event ◽

Chromosome Mapping ◽

The Other ◽

Other Hand ◽

Interchromosomal Rearrangement ◽

Insight Into ◽

Phalacrocorax Brasilianus

Interchromosomal rearrangements involving microchromosomes are rare events in birds. To date, they have been found mostly in Psittaciformes, Falconiformes, and Cuculiformes, although only a few orders have been analyzed. Hence, cytogenomic studies focusing on microchromosomes in species belonging to different bird orders are essential to shed more light on the avian chromosome and karyotype evolution. Based on this, we performed a comparative chromosome mapping for chicken microchromosomes 10 to 28 using interspecies BAC-based FISH hybridization in five species, representing four Neoaves orders (Caprimulgiformes, Piciformes, Suliformes, and Trogoniformes). Our results suggest that the ancestral microchromosomal syntenies are conserved in Pteroglossus inscriptus (Piciformes), Ramphastos tucanus tucanus (Piciformes), and Trogon surrucura surrucura (Trogoniformes). On the other hand, chromosome reorganization in Phalacrocorax brasilianus (Suliformes) and Hydropsalis torquata (Caprimulgiformes) included fusions involving both macro- and microchromosomes. Fissions in macrochromosomes were observed in P. brasilianus and H. torquata. Relevant hypothetical Neognathae and Neoaves ancestral karyotypes were reconstructed to trace these rearrangements. We found no interchromosomal rearrangement involving microchromosomes to be shared between avian orders where rearrangements were detected. Our findings suggest that convergent evolution involving microchromosomal change is a rare event in birds and may be appropriate in cytotaxonomic inferences in orders where these rearrangements occurred.

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Structural analysis of cross α-helical nanotubes provides insight into the designability of filamentous peptide nanomaterials

Nature Communications ◽

10.1038/s41467-020-20689-w ◽

2021 ◽

Vol 12 (1) ◽

Author(s):

Fengbin Wang ◽

Ordy Gnewou ◽

Charles Modlin ◽

Leticia C. Beltran ◽

Chunfu Xu ◽

...

Keyword(s):

Structural Analysis ◽

Synthetic Peptide ◽

Quaternary Structure ◽

De Novo ◽

Rational Approach ◽

Lateral Interactions ◽

Protein Assemblies ◽

Self Assembling ◽

Arginine Residues ◽

Insight Into

AbstractThe exquisite structure-function correlations observed in filamentous protein assemblies provide a paradigm for the design of synthetic peptide-based nanomaterials. However, the plasticity of quaternary structure in sequence-space and the lability of helical symmetry present significant challenges to the de novo design and structural analysis of such filaments. Here, we describe a rational approach to design self-assembling peptide nanotubes based on controlling lateral interactions between protofilaments having an unusual cross-α supramolecular architecture. Near-atomic resolution cryo-EM structural analysis of seven designed nanotubes provides insight into the designability of interfaces within these synthetic peptide assemblies and identifies a non-native structural interaction based on a pair of arginine residues. This arginine clasp motif can robustly mediate cohesive interactions between protofilaments within the cross-α nanotubes. The structure of the resultant assemblies can be controlled through the sequence and length of the peptide subunits, which generates synthetic peptide filaments of similar dimensions to flagella and pili.

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Extended haplotype-phasing of long-read de novo genome assemblies using Hi-C

Nature Communications ◽

10.1038/s41467-020-20536-y ◽

2021 ◽

Vol 12 (1) ◽

Author(s):

Zev N. Kronenberg ◽

Arang Rhie ◽

Sergey Koren ◽

Gregory T. Concepcion ◽

Paul Peluso ◽

...

Keyword(s):

Zebra Finch ◽

Cultured Cells ◽

De Novo ◽

Single Cells ◽

Variant Calling ◽

Chromatin Interaction ◽

Extended Haplotype ◽

Benchmark Datasets ◽

And Performance ◽

Genome Assemblies

AbstractHaplotype-resolved genome assemblies are important for understanding how combinations of variants impact phenotypes. To date, these assemblies have been best created with complex protocols, such as cultured cells that contain a single-haplotype (haploid) genome, single cells where haplotypes are separated, or co-sequencing of parental genomes in a trio-based approach. These approaches are impractical in most situations. To address this issue, we present FALCON-Phase, a phasing tool that uses ultra-long-range Hi-C chromatin interaction data to extend phase blocks of partially-phased diploid assembles to chromosome or scaffold scale. FALCON-Phase uses the inherent phasing information in Hi-C reads, skipping variant calling, and reduces the computational complexity of phasing. Our method is validated on three benchmark datasets generated as part of the Vertebrate Genomes Project (VGP), including human, cow, and zebra finch, for which high-quality, fully haplotype-resolved assemblies are available using the trio-based approach. FALCON-Phase is accurate without having parental data and performance is better in samples with higher heterozygosity. For cow and zebra finch the accuracy is 97% compared to 80–91% for human. FALCON-Phase is applicable to any draft assembly that contains long primary contigs and phased associate contigs.

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Natural Variation in Plant Pluripotency and Regeneration

Plants ◽

10.3390/plants9101261 ◽

2020 ◽

Vol 9 (10) ◽

pp. 1261

Author(s):

Robin Lardon ◽

Danny Geelen

Keyword(s):

De Novo ◽

Shoot Organogenesis ◽

In Vitro Regeneration ◽

Relative Role ◽

Root Explants ◽

Experimental Systems ◽

Complex Process ◽

Insight Into ◽

Molecular Framework

Plant regeneration is essential for survival upon wounding and is, hence, considered to be a strong natural selective trait. The capacity of plant tissues to regenerate in vitro, however, varies substantially between and within species and depends on the applied incubation conditions. Insight into the genetic factors underlying this variation may help to improve numerous biotechnological applications that exploit in vitro regeneration. Here, we review the state of the art on the molecular framework of de novo shoot organogenesis from root explants in Arabidopsis, which is a complex process controlled by multiple quantitative trait loci of various effect sizes. Two types of factors are distinguished that contribute to natural regenerative variation: master regulators that are conserved in all experimental systems (e.g., WUSCHEL and related homeobox genes) and conditional regulators whose relative role depends on the explant and the incubation settings. We further elaborate on epigenetic variation and protocol variables that likely contribute to differential explant responsivity within species and conclude that in vitro shoot organogenesis occurs at the intersection between (epi) genetics, endogenous hormone levels, and environmental influences.

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Steroidogenic Factor-1 (SF-1)-Driven Differentiation of Murine Embryonic Stem (ES) Cells into a Gonadal Lineage

Endocrinology ◽

10.1210/en.2011-0219 ◽

2011 ◽

Vol 152 (7) ◽

pp. 2870-2882 ◽

Cited By ~ 24

Author(s):

Unmesh Jadhav ◽

J. Larry Jameson

Keyword(s):

Target Genes ◽

De Novo ◽

Embryoid Body ◽

Es Cells ◽

Embryonic Stem ◽

Cell Lineage ◽

Culture Conditions ◽

Steroidogenic Factor 1 ◽

Lineage Differentiation ◽

And Function

Steroidogenic factor 1 (SF-1) is essential for the development and function of steroidogenic tissues. Stable incorporation of SF-1 into embryonic stem cells (SF-1-ES cells) has been shown to prime the cells for steroidogenesis. When provided with exogenous cholesterol substrate, and after treatment with retinoic acid and cAMP, SF-1-ES cells produce progesterone but do not produce other steroids such as cortisol, estradiol, or testosterone. In this study, we explored culture conditions that optimize SF-1-mediated differentiation of ES cells into defined steroidogenic lineages. When embryoid body formation was used to facilitate cell lineage differentiation, SF-1-ES cells were found to be restricted in their differentiation, with fewer cells entering neuronal pathways and a larger fraction entering the steroidogenic lineage. Among the differentiation protocols tested, leukemia inhibitory factor (LIF) removal, followed by prolonged cAMP treatment was most efficacious for inducing steroidogenesis in SF-1-ES cells. In this protocol, a subset of SF-1-ES cells survives after LIF withdrawal, undergoes morphologic differentiation, and recovers proliferative capacity. These cells are characterized by induction of steroidogenic enzyme genes, use of de novo cholesterol, and production of multiple steroids including estradiol and testosterone. Microarray studies identified additional pathways associated with SF-1 mediated differentiation. Using biotinylated SF-1 in chromatin immunoprecipitation assays, SF-1 was shown to bind directly to multiple target genes, with induction of binding to some targets after steroidogenic treatment. These studies indicate that SF-1 expression, followed by LIF removal and treatment with cAMP drives ES cells into a steroidogenic pathway characteristic of gonadal steroid-producing cells.

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Identification of target genes and a unique cis element regulated by IRF-8 in developing macrophages

Blood ◽

10.1182/blood-2005-01-0080 ◽

2005 ◽

Vol 106 (6) ◽

pp. 1938-1947 ◽

Cited By ~ 96

Author(s):

Tomohiko Tamura ◽

Pratima Thotakura ◽

Tetsuya S. Tanaka ◽

Minoru S. H. Ko ◽

Keiko Ozato

Keyword(s):

Transcription Factor ◽

Cystatin C ◽

Target Genes ◽

De Novo ◽

Consensus Sequence ◽

Binding Motif ◽

Microarray Gene Expression ◽

Cathepsin C ◽

Cis Element

Abstract Interferon regulatory factor-8 (IRF-8)/interferon consensus sequence–binding protein (ICSBP) is a transcription factor that controls myeloid-cell development. Microarray gene expression analysis of Irf-8-/- myeloid progenitor cells expressing an IRF-8/estrogen receptor chimera (which differentiate into macrophages after addition of estradiol) was used to identify 69 genes altered by IRF-8 during early differentiation (62 up-regulated and 7 down-regulated). Among them, 4 lysosomal/endosomal enzyme-related genes (cystatin C, cathepsin C, lysozyme, and prosaposin) did not require de novo protein synthesis for induction, suggesting that they were direct targets of IRF-8. We developed a reporter assay system employing a self-inactivating retrovirus and analyzed the cystatin C and cathepsin C promoters. We found that a unique cis element mediates IRF-8–induced activation of both promoters. Similar elements were also found in other IRF-8 target genes with a consensus sequence (GAAANN[N]GGAA) comprising a core IRF-binding motif and an Ets-binding motif; this sequence is similar but distinct from the previously reported Ets/IRF composite element. Chromatin immunoprecipitation assays demonstrated that IRF-8 and the PU.1 Ets transcription factor bind to this element in vivo. Collectively, these data indicate that IRF-8 stimulates transcription of target genes through a novel cis element to specify macrophage differentiation.

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