Nfic regulates tooth root patterning and growth

Nuclear Factor I Family Members are Key Transcription Factors Regulating Gene Expression

The Nuclear Factor I (NFI) family of transcription factors (TFs) plays key roles in cellular differentiation, proliferation, and homeostasis. As such, NFI family members engage in a large number of interactions with other proteins and chromatin. However, despite their well-established significance, the NFIs' interactomes, their dynamics, and their functions have not been comprehensively examined. Here, we employed complementary omics-level techniques, i.e. interactomics (affinity purification mass spectrometry (AP-MS) and proximity-dependent biotinylation (BioID)), and chromatin immunoprecipitation sequencing (ChIP-Seq), to obtain a comprehensive view of the NFI proteins and their interactions in different cell lines. Our analyses included all four NFI family members, and a less-studied short isoform of NFIB (NFIB4), which lacks the DNA binding domain. We observed that, despite exhibiting redundancy, each family member had unique high-confidence interactors and target genes, suggesting distinct roles within the transcriptional regulatory networks. The study revealed that NFIs interact with other TFs to co-regulate a broad range of regulatory networks and cellular processes. Notably, time-dependent proximity-labeling unveiled a highly dynamic nature of NFI protein-protein interaction networks and hinted at the temporal modulation of NFI interactions. Furthermore, gene ontology (GO) enrichment analysis of NFI interactome and targetome revealed the involvement of NFIs in transcriptional regulation, chromatin organization, cellular signaling pathways, and pathways related to cancer. Additionally, we observed that NFIB4 engages with proteins associated with mRNA regulation, which suggests that NFIs have roles beyond traditional DNA binding and transcriptional modulation. We propose that NFIs may function as potential pioneering TFs, given their role in regulating the DNA binding ability of other TFs and their interactions with key chromatin remodeling complexes, thereby influencing a wide range of cellular processes. These insights into NFI protein-protein interactions and their dynamic, context-dependent nature provide a deeper understanding of gene regulation mechanisms and hint at the role of NFIs as master regulators.

Knockdown of NFIC Promotes Bovine Myoblast Proliferation through the CENPF/CDK1 Axis

As cellular transcription factors and DNA replicators, nuclear factor I (NFI) family members play an important role in mammalian development. However, there is still a lack of research on the muscle regeneration of NFI family members in cattle. In this study, the analysis of NFI family factors was conducted on their characterization, phylogenetics, and functional domains. We found that NFI family members were relatively conserved among different species, but there was heterogeneity in amino acid sequences, DNA coding sequences, and functional domain among members. Furthermore, among NFI family factors, we observed that NFIC exhibited highly expression in bovine muscle tissues, particularly influencing the expression of proliferation marker genes in myoblasts. To investigate the influence of NFIC on myoblast proliferation, we knocked down NFIC (si-NFIC) and found that the proliferation of myoblasts was significantly promoted. In terms of regulation mechanism, we identified that si-NFIC could counteract the inhibitory effect of the cell cycle inhibitor RO-3306. Interestingly, CENPF, as the downstream target gene of NFIC, could affect the expression of CDK1, CCNB1, and actively regulate the cell cycle pathway and cell proliferation. In addition, when CENPF was knocked down, the phosphorylation of p53 and the expression of Bax were increased, but the expression of Bcl2 was inhibited. Our findings mainly highlight the mechanism by which NFIC acts on the CENPF/CDK1 axis to regulate the proliferation of bovine myoblasts.

A Wnt10a-Notch signaling axis controls Hertwig's epithelial root sheath cell behaviors during root furcation patterning

Human with bi-allelic WNT10A mutations and epithelial Wnt10a knockout mice present enlarged pulp chamber and apical displacement of the root furcation of multi-rooted teeth, known as taurodontism; thus, indicating the critical role of Wnt10a in tooth root morphogenesis. However, the endogenous mechanism by which epithelial Wnt10a regulates Hertwig's epithelial root sheath (HERS) cellular behaviors and contributes to root furcation patterning remains unclear. In this study, we found that HERS in the presumptive root furcating region failed to elongate at an appropriate horizontal level in K14-Cre;Wnt10afl/fl mice from post-natal day 0.5 (PN0.5) to PN4.5. EdU assays and immunofluorescent staining of cyclin D1 revealed significantly decreased proliferation activity of inner enamel epithelial (IEE) cells of HERS in K14-Cre;Wnt10afl/fl mice at PN2.5 and PN3.5. Immunofluorescent staining of E-Cadherin and acetyl-α-Tubulin demonstrated that the IEE cells of HERS tended to divide perpendicularly to the horizontal plane, which impaired the horizontal extension of HERS in the presumptive root furcating region of K14-Cre;Wnt10afl/fl mice. RNA-seq and immunofluorescence showed that the expressions of Jag1 and Notch2 were downregulated in IEE cells of HERS in K14-Cre;Wnt10afl/fl mice. Furthermore, after activation of Notch signaling in K14-Cre;Wnt10afl/fl molars by Notch2 adenovirus and kidney capsule grafts, the root furcation defect was partially rescued. Taken together, our study demonstrates that an epithelial Wnt10a-Notch signaling axis is crucial for modulating HERS cell proper proliferation and horizontal-oriented division during tooth root furcation morphogenesis.

The Development of Dentin Microstructure Is Controlled by the Type of Adjacent Epithelium

Considerable amount of research has been focused on dentin mineralization, odontoblast differentiation, and their application in dental tissue engineering. However, very little is known about the differential role of functionally and spatially distinct types of dental epithelium during odontoblast development. Here we show morphological and functional differences in dentin located in the crown and roots of mouse molar and analogous parts of continuously growing incisors. Using a reporter (DSPP-cerulean/DMP1-cherry) mouse strain and mice with ectopic enamel (Spry2^+/- ;Spry4^-/- ), we show that the different microstructure of dentin is initiated in the very beginning of dentin matrix production and is maintained throughout the whole duration of dentin growth. This phenomenon is regulated by the different inductive role of the adjacent epithelium. Thus, based on the type of interacting epithelium, we introduce more generalized terms for two distinct types of dentins: cementum versus enamel-facing dentin. In the odontoblasts, which produce enamel-facing dentin, we identified uniquely expressed genes (Dkk1, Wisp1, and Sall1) that were either absent or downregulated in odontoblasts, which form cementum-facing dentin. This suggests the potential role of Wnt signalling on the dentin structure patterning. Finally, we show the distribution of calcium and magnesium composition in the two developmentally different types of dentins by utilizing spatial element composition analysis (LIBS). Therefore, variations in dentin inner structure and element composition are the outcome of different developmental history initiated from the very beginning of tooth development. Taken together, our results elucidate the different effects of dental epithelium, during crown and root formation on adjacent odontoblasts and the possible role of Wnt signalling which together results in formation of dentin of different quality. © 2021 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR).

Hsa-miRNA-143-3p regulates the odontogenic differentiation of human stem cells from the apical papilla by targeting NFIC

AIM

To evaluate the effects of hsa-miRNA-143-3p on the cytodifferentiation of human stem cells from the apical papilla (hSCAPs) and the post-transcriptional regulation of Nuclear factor I-C (NFIC).

METHODOLOGY

miRNA expression profiles in human immature permanent teeth and during hSCAP differentiation were examined. hSCAPs were treated with miR-143-3p overexpression or silencing viruses, and the proliferation and odontogenic and osteogenic differentiation of these stem cells, and the involvement of the NFIC pathway, were investigated. Luciferase reporter and NFIC mutant plasmids were used to confirm NFIC mRNA as a direct target of miR-143-3p. NFIC expression analysis in the miR-143-3p overexpressing hSCAPs was used to investigate whether miR-143-3p functioned by targeting NFIC. Student's t-test and chi-square tests were used for statistical analysis.

RESULTS

miR-143-3p expression was screened by microarray profiling and was found to be significantly reduced during hSCAP differentiation (p < .05). Overexpression of miR-143-3p inhibited the mineralization of hSCAPs significantly (p < .05) and downregulated the levels of odontogenic differentiation markers (NFIC [p < .05], DSP [p < .01] and KLF4 [p < .01]), whereas silencing of miR-143-3p had the opposite effect. The luciferase reporter gene detection and bioinformatic approaches identified NFIC mRNA as a potential target of miR-143-3p. NFIC overexpression reversed the inhibitory effect of miR-143-3p on the odontogenic differentiation of hSCAPs.

CONCLUSIONS

miR-143-3p maintained the stemness of hSCAPs and modulated their differentiation negatively by directly targeting NFIC. Thus, inhibition of this miRNA represents a potential strategy to promote the regeneration of damaged tooth roots.

Intertwined Signaling Pathways Governing Tooth Development: A Give-and-Take Between Canonical Wnt and Shh

Teeth play essential roles in life. Their development relies on reciprocal interactions between the ectoderm-derived dental epithelium and the underlying neural crest-originated mesenchyme. This odontogenic process serves as a prototype model for the development of ectodermal appendages. In the mouse, developing teeth go through distinct morphological phases that are tightly controlled by epithelial signaling centers. Crucial molecular regulators of odontogenesis include the evolutionarily conserved Wnt, BMP, FGF and sonic hedgehog (Shh) pathways. These signaling modules do not act on their own, but are closely intertwined during tooth development, thereby outlining the path to be taken by specific cell populations including the resident dental stem cells. Recently, pivotal Wnt-Shh interaction and feedback loops have been uncovered during odontogenesis, showing conservation in other developing ectodermal appendages. This review provides an integrated overview of the interplay between canonical Wnt and Shh throughout mouse tooth formation stages, extending from the initiation of dental placode to the fully formed adult tooth.

The critical role of nuclear factor I-C in tooth development

OBJECTIVES

Nuclear factor I-C (NFIC) plays a critical role in regulating epithelial-mesenchymal crosstalk during tooth development. However, it remains largely unknown about how NFIC functions in dentin and enamel formation. In the present review, we aim to summarize the most recent discoveries in the field and gain a better understanding of the roles NFIC performs during tooth formation.

SUBJECTS AND METHODS

Nfic^-/- mice exhibit human dentin dysplasia type I (DDI)-like phenotypes signified by enlarged pulp chambers, the presence of short-root anomaly, and failure of odontoblast differentiation. Although loss of NFIC has little effect on molar crown morphology, researchers have detected aberrant microstructures of enamel in the incisors. Recently, accumulating evidence has further uncovered the novel function of NFIC in the process of enamel and dentin formation.

RESULTS

During epithelial-mesenchyme crosstalk, the expression of NFIC is under the control of SHH-PTCH-SMO-GLI1 pathway. NFIC is closely involved in odontoblast lineage cells proliferation and differentiation, and the maintenance of NFIC protein level in cytoplasm is negatively regulated by TGF-β signaling pathway. In addition, NFIC has mild effect on ameloblast differentiation, enamel mineralization and cementum formation.

CONCLUSIONS

NFIC plays an important role in tooth development and is required for the formation of dentin, enamel as well as cementum.

Epithelial Bone Morphogenic Protein 2 and 4 Are Indispensable for Tooth Development

The Bmp2 and Bmp4 expressed in root mesenchyme were essential for the patterning and cellular differentiation of tooth root. The role of the epithelium-derived Bmps in tooth root development, however, had not been reported. In this study, we found that the double abrogation of Bmp2 and Bmp4 from mouse epithelium caused short root anomaly (SRA). The K14-cre;Bmp2^f/f;Bmp4^f/f mice exhibited a persistent Hertwig’s Epithelial Root Sheath (HERS) with the reduced cell death, and the down-regulated BMP-Smad4 and Erk signaling pathways. Moreover, the Shh expression in the HERS, the Shh-Gli1 signaling, and Nfic expression in the root mesenchyme of the K14-cre;Bmp2^f/f;Bmp4^f/f mice were also decreased, indicating a disrupted epithelium- mesenchyme interaction between HERS and root mesenchyme. Such disruption suppressed the Osx and Dspp expression in the root mesenchyme, indicating an impairment on the differentiation and maturation of root odontoblasts. The impaired differentiation and maturation of root odontoblasts could be rescued partially by transgenic Dspp. Therefore, although required in a low dosage and with a functional redundancy, the epithelial Bmp2 and Bmp4 were indispensable for the HERS degeneration, as well as the differentiation and maturation of root mesenchyme.

USP34 regulates tooth root morphogenesis by stabilizing NFIC

Tooth root morphogenesis involves two biological processes, root elongation and dentinogenesis, which are guaranteed by downgrowth of Hertwig's epithelial root sheath (HERS) and normal odontoblast differentiation. Ubiquitin-dependent protein degradation has been reported to precisely regulate various physiological processes, while its role in tooth development is still elusive. Here we show ubiquitin-specific protease 34 (USP34) plays a pivotal role in root formation. Deletion of Usp34 in dental mesenchymal cells leads to short root anomaly, characterized by truncated roots and thin root dentin. The USP34-deficient dental pulp cells (DPCs) exhibit decreased odontogenic differentiation with downregulation of nuclear factor I/C (NFIC). Overexpression of NFIC partially restores the impaired odontogenic potential of DPCs. These findings indicate that USP34-dependent deubiquitination is critical for root morphogenesis by stabilizing NFIC.

Lhx6 regulates canonical Wnt signaling to control the fate of mesenchymal progenitor cells during mouse molar root patterning

Mammalian tooth crown formation has long served as a model for investigating how patterning and morphogenesis are orchestrated during development. However, the mechanism underlying root patterning and morphogenesis remains poorly understood. In this study, we find that Lhx6 labels a subpopulation of root progenitor cells in the apical dental mesenchyme, which is closely associated with furcation development. Loss of Lhx6 leads to furcation and root number defects, indicating that Lhx6 is a key root patterning regulator. Among the multiple cellular events regulated by Lhx6 is the odontoblast fate commitment of progenitor cells, which it controls in a cell-autonomous manner. Specifically, Lhx6 loss leads to elevated expression of the Wnt antagonist Sfrp2 and down-regulation of Wnt signaling in the furcation region, while overactivation of Wnt signaling in Lhx6+ progenitor cells partially restore the furcation defects in Lhx6-/- mice. Collectively, our findings have important implications for understanding organ morphogenesis and future strategies for tooth root regeneration.

METTL3-Mediated m6 A mRNA Methylation Modulates Tooth Root Formation by Affecting NFIC Translation

N6-methyladenosine (m⁶ A), as a eukaryotic mRNA modification catalyzed by methyltransferase METTL3, is involved in various processes of development or diseases via regulating RNA metabolism. However, the effect of METTL3-mediated m⁶ A modification in tooth development has remained elusive. Here we show that METTL3 is prevalently expressed in odontoblasts, dental pulp cells, dental follicle cells, and epithelial cells in Hertwig's epithelial root sheath during tooth root formation. Depletion of METTL3 in human dental pulp cells (hDPCs) impairs proliferation, migration, and odontogenic differentiation. Furthermore, conditional knockout of Mettl3 in Osterix-expressing cells leads to short molar roots and thinner root dentin featured by decreased secretion of pre-dentin matrix and formation of the odontoblast process. Mechanistically, loss of METTL3 cripples the translational efficiency of the key root-forming regulator nuclear factor I-C (NFIC). The odontogenic capacity of METTL3-silenced hDPCs is partially rescued via overexpressing NFIC. Our findings suggest that m⁶ A methyltransferase METTL3 is crucial for tooth root development, uncovering a novel epigenetic mechanism in tooth root formation. © 2020 American Society for Bone and Mineral Research (ASBMR).

Methylphenidate effects on mice odontogenesis and connections with human odontogenesis

The purpose of this study is to evaluate the effects of Methylphenidate exposure on mice odontogenesis and connect them by bioinformatics with human odontogenesis. Thirty-two pregnant Swiss mice were divided into treated group and control group, which received, respectively, 5 mg/kg of Methylphenidate and saline solution from the 5th to the 17th day of pregnancy. The mouse embryos tooth germs were analyzed through optical microscopy, and the data collected were analyzed statistically by Fisher's exact test. The presence and similarity of Methylphenidate-associated genes (Pharmgkb database) in both organisms and their interaction with dental development genes (AmiGO2 database) were verified on STRING database. Rates of tooth germ malformations were higher in treated than in control group (Control: 18; Treated: 27; p = 0.035). Mouse embryo malformations were connected with 238 interactions between 69 dental development genes with 35 Methylphenidate genes. Fourteen interactions for four Methylphenidate genes with four dental development genes, with human experimental data, were connected with mouse phenotype data. By homology, the interactions and conservation of proteins/genes may indicate similar outcomes for both organisms. The exposure to Methylphenidate during pregnancy affected odontogenesis in mouse embryos and may affect human odontogenesis. The study of malformations in mice, with a bioinformatics approach, could contribute to understanding of the Methylphenidate effect on embryo development. These results may provide novel hypotheses for further testing and reinforce the FDA protocol: as Methylphenidate is included in category C, its use during pregnancy should be considered if the benefits outweigh the risks.

AFF4 enhances odontogenic differentiation of human dental pulp cells

AFF4 is a component of super elongation complex (SECs) and functions as a scaffold protein to bridge the transcription elongation factors. It is associated with leukemia, HIV transcription, and head neck cancer. However, its role in odontogenic differentiation of dental pulp cells (DPCs) is unclear. Here, we show the expression of AFF4 is increased during odontogenesis. Depletion of AFF4 in human DPCs leads to a decrease of alkaline phosphatase (ALP) activity, calcium mineralization and odontogenic-related genes expression. On the contrary, Lentivirus-mediated overexpression of AFF4 induces the odontogenic potential of DPCs. Mechanistically, we found AFF4 regulates the transcription of NFIC, a key factor for tooth root formation. Overexpression of NFIC successfully rescues the restricted differentiation of AFF4-depleted cells. Our data demonstrate that AFF4 serves as a previously unknown regulator of odontogenesis.

Mesenchymal Progenitor Regulation of Tooth Eruption: A View from PTHrP

Tooth eruption is a unique biological process by which highly mineralized tissues emerge into the outer world, and it occurs concomitantly with tooth root formation. These 2 processes have been considered independent phenomena; however, recent studies support the theory that they are indeed intertwined. Dental mesenchymal progenitor cells in the dental follicle lie at the heart of the coupling of these 2 processes, providing a source for diverse mesenchymal cells that support formation of the highly functional tooth root and the periodontal attachment apparatus, while facilitating formation of osteoclasts. These cells are regulated by autocrine signaling by parathyroid hormone-related protein (PTHrP) and its parathyroid hormone/PTHrP receptor PPR. This PTHrP-PPR signaling appears to crosstalk with other signaling pathways and regulates proper cell fates of mesenchymal progenitor cell populations. Disruption of this autocrine PTHrP-PPR signaling in these cells leads to defective formation of the periodontal attachment apparatus, tooth root malformation, and failure of tooth eruption in molars, which essentially recapitulate primary failure of eruption in humans, a rare genetic disorder exclusively affecting tooth eruption. Diversity and distinct functionality of these mesenchymal progenitor cell populations that regulate tooth eruption and tooth root formation are beginning to be unraveled.

[The role of bone morphogenetic protein signaling pathway in tooth root development]

The bone morphogenetic protein (BMP) family is an important factor in the regulation of cell ular life activities and in the development of almost all tissues. BMP-mediated signaling plays an important role in tooth root development, which is a part of tooth development. Epithelial and mesenchymal interactions are involved in tooth root development, but the BMP signaling pathway has a different effect on tooth root development in epithelial and mesenchymal. This review summarizes the advances of BMP signaling in tooth root development.

Pathogenesis of primordial odontogenic tumour based on tumourigenesis and odontogenesis

OBJECTIVE

Primordial odontogenic tumour (POT) is a rare benign mixed epithelial and mesenchymal odontogenic tumour. POT is composed of dental papilla-like tissue covered with cuboidal to columnar epithelium that resembles to inner and outer enamel epithelium of the enamel organ without dental hard tissue formation. The aim of this study was to examine pathogenesis of POT based on tumourigenesis and odontogenesis.

SUBJECTS AND METHODS

Six cases of POT were submitted for study. DNA analysis and transcriptome analysis were performed by next-generation sequencing. Expression of amelogenin, ameloblastin and dentin sialophosphoprotein (DSPP) was examined by immunohistochemistry.

RESULTS

There were no gene mutations detected in any of analysed 151 cancer- and 42 odontogenesis-associated genes. Enamel protein-coding genes of Amelx, Ambn and Enam, and dentin protein-coding genes of Col1a1, Dspp, Nes and Dmp1 were expressed, whereas expression of dentinogenesis-associated genes of Bglap, Ibsp and Nfic was negative or very weak suggesting inhibition of dentin formation in POT after odontoblast differentiation. Immunoreactivity of amelogenin, ameloblastin and DSPP was detected in POT.

CONCLUSIONS

Pathogenesis of POT is considered to be genetically different from other odontogenic tumours. It is suggested that inhibition of enamel and dentin formation in POT is due to defects in dentin formation process.

Signaling Pathways Critical for Tooth Root Formation

Tooth is made of an enamel-covered crown and a cementum-covered root. Studies on crown dentin formation have been a major focus in tooth development for several decades. Interestingly, the population prevalence for genetic short root anomaly (SRA) with no apparent defects in crown is close to 1.3%. Furthermore, people with SRA itself are predisposed to root resorption during orthodontic treatment. The discovery of the unique role of Nfic (nuclear factor I C; a transcriptional factor) in controlling root but not crown dentin formation points to a new concept: tooth crown and root have different control mechanisms. Further genetic mechanism studies have identified more key molecules (including Osterix, β-catenin, and sonic hedgehog) that play a critical role in root formation. Extensive studies have also revealed the critical role of Hertwig's epithelial root sheath in tooth root formation. In addition, Wnt10a has recently been found to be linked to multirooted tooth furcation formation. These exciting findings not only fill the critical gaps in our understanding about tooth root formation but will aid future research regarding the identifying factors controlling tooth root size and the generation of a whole "bio-tooth" for therapeutic purposes. This review starts with human SRA and mainly focuses on recent progress on the roles of NFIC-dependent and NFIC-independent signaling pathways in tooth root formation. Finally, this review includes a list of the various Cre transgenic mouse lines used to achieve tooth root formation-related gene deletion or overexpression, as well as strengths and limitations of each line.

The Impact of the Eda Pathway on Tooth Root Development

The Eda pathway ( Eda, Edar, Edaradd) plays an important role in tooth development, determining tooth number, crown shape, and enamel formation. Here we show that the Eda pathway also plays a key role in root development. Edar (the receptor) is expressed in Hertwig's epithelial root sheath (HERS) during root development, with mutant mice showing a high incidence of taurodontism: large pulp chambers lacking or showing delayed bifurcation or trifurcation of the roots. The mouse upper second molars in the Eda pathway mutants show the highest incidence of taurodontism, this enhanced susceptibility being matched in human patients with mutations in EDA-A1. These taurodont teeth form due to defects in the direction of extension of the HERS from the crown, associated with a more extensive area of proliferation of the neighboring root mesenchyme. In those teeth where the angle at which the HERS extends from the crown is very wide and therefore more vertical, the mutant HERSs fail to reach toward the center of the tooth in the normal furcation region, and taurodont teeth are created. The phenotype is variable, however, with milder changes in angle and proliferation leading to normal or delayed furcation. This is the first analysis of the role of Eda in the root, showing a direct role for this pathway during postnatal mouse development, and it suggests that changes in proliferation and angle of HERS may underlie taurodontism in a range of syndromes.

De Novo Genome and Transcriptome Assembly of the Canadian Beaver (Castor canadensis)

The Canadian beaver (Castor canadensis) is the largest indigenous rodent in North America. We report a draft annotated assembly of the beaver genome, the first for a large rodent and the first mammalian genome assembled directly from uncorrected and moderate coverage (< 30 ×) long reads generated by single-molecule sequencing. The genome size is 2.7 Gb estimated by k-mer analysis. We assembled the beaver genome using the new Canu assembler optimized for noisy reads. The resulting assembly was refined using Pilon supported by short reads (80 ×) and checked for accuracy by congruency against an independent short read assembly. We scaffolded the assembly using the exon–gene models derived from 9805 full-length open reading frames (FL-ORFs) constructed from the beaver leukocyte and muscle transcriptomes. The final assembly comprised 22,515 contigs with an N50 of 278,680 bp and an N50-scaffold of 317,558 bp. Maximum contig and scaffold lengths were 3.3 and 4.2 Mb, respectively, with a combined scaffold length representing 92% of the estimated genome size. The completeness and accuracy of the scaffold assembly was demonstrated by the precise exon placement for 91.1% of the 9805 assembled FL-ORFs and 83.1% of the BUSCO (Benchmarking Universal Single-Copy Orthologs) gene set used to assess the quality of genome assemblies. Well-represented were genes involved in dentition and enamel deposition, defining characteristics of rodents with which the beaver is well-endowed. The study provides insights for genome assembly and an important genomics resource for Castoridae and rodent evolutionary biology.