Developmental Stage-specific Manner Research Articles

Effect of valproic acid on the formation and migration of cranial neural crest cells at the early developmental stages in rat embryos.

Cranial neural crest cells (NCCs) are critical for craniofacial development. The administration of valproic acid (VPA) to pregnant females causes craniofacial malformations in offspring. However, the in vivo influence of VPA on mammalian cranial NCCs remains unclear. In this study, we aimed to elucidate the developmental stage-specific effect of VPA on cranial NCCs through the administration of a single dose of VPA to pregnant rat females immediately prior to the formation of the cranial neural crest (NC). We performed whole-mount immunohistochemistry or in situ hybridization to examine localization changes of gene transcripts associated with the epithelial-mesenchymal transition of the cranial NC (i.e., cranial NCC formation) and cranial NCC migration. The results showed that Hoxa2 mRNA was abnormally detected and Sox9 mRNA expression was decreased in the midbrain-rhombomere (R) 1/2 NC, which forms cranial NCCs that migrate to the frontonasal mass (FNM) and branchial arch (BA) 1, through VPA administration, thus reducing the formation of SNAI2-positive NCCs. Hoxa2-positive NCCs were detected normally in BA2 and abnormally in FNM and BA1, which are normally Hox-free, implying VPA-induced abnormal cranial NCC migration. In vitro verification experiments using the whole embryo culture system revealed that midbrain-R4 NCC migration was abnormal. These results indicate that VPA reduces the formation/delamination of the midbrain-R1/2 NCCs in a developmental stage-specific manner and subsequently causes the abnormal migration of R4 NCCs, which suggests that the abnormal formation and migration of cranial NCCs contribute to the inhibition of axonal elongation in the trigeminal nerve and a reduction in head size.

Regulation potential of transcribed simple repeated sequences in developing neurons

Simple repeated sequences (SRSs), defined as tandem iterations of microsatellite- to satellite-sized DNA units, occupy a substantial part of the human genome. Some of these elements are known to be transcribed in the context of repeat expansion disorders. Mounting evidence suggests that the transcription of SRSs may also contribute to normal cellular functions. Here, we used genome-wide bioinformatics approaches to systematically examine SRS transcriptional activity in cells undergoing neuronal differentiation. We identified thousands of long noncoding RNAs containing >200-nucleotide-long SRSs (SRS-lncRNAs), with hundreds of these transcripts significantly upregulated in the neural lineage. We show that SRS-lncRNAs often originate from telomere-proximal regions and that they have a strong potential to form multivalent contacts with a wide range of RNA-binding proteins. Our analyses also uncovered a cluster of neurally upregulated SRS-lncRNAs encoded in a centromere-proximal part of chromosome 9, which underwent an evolutionarily recent segmental duplication. Using a newly established in vitro system for rapid neuronal differentiation of induced pluripotent stem cells, we demonstrate that at least some of the bioinformatically predicted SRS-lncRNAs, including those encoded in the segmentally duplicated part of chromosome 9, indeed increase their expression in developing neurons to readily detectable levels. These and other lines of evidence suggest that many SRSs may be expressed in a cell type and developmental stage-specific manner, providing a valuable resource for further studies focused on the functional consequences of SRS-lncRNAs in the normal development of the human brain, as well as in the context of neurodevelopmental disorders.

Leveraging the developmental neuroscience of caregiving to promote resilience among youth exposed to adversity.

Early adversity is a major risk factor for the emergence of psychopathology across development. Identifying mechanisms that support resilience, or favorable mental health outcomes despite exposure to adversity, is critical for informing clinical intervention and guiding policy to promote youth mental health. Here we propose that caregivers play a central role in fostering resilience among children exposed to adversity via caregiving influences on children's corticolimbic circuitry and emotional functioning. We first delineate the numerous ways that caregivers support youth emotional learning and regulation and describe how early attachment lays the foundation for optimal caregiver support of youth emotional functioning in a developmental stage-specific manner. Second, we outline neural mechanisms by which caregivers foster resilience-namely, by modulating offspring corticolimbic circuitry to support emotion regulation and buffer stress reactivity. Next, we highlight the importance of developmental timing and sensitive periods in understanding caregiving-related mechanisms of resilience. Finally, we discuss clinical implications of this line of research and how findings can be translated to guide policy that promotes the well-being of youth and families.

RNA Transcript Diversity in Neuromuscular Research.

Three decades since the Human Genome Project began, scientists have now identified more then 25,000 protein coding genes in the human genome. The vast majority of the protein coding genes (> 90%) are multi-exonic, with the coding DNA being interrupted by intronic sequences, which are removed from the pre-mRNA transcripts before being translated into proteins, a process called splicing maturation. Variations in this process, i.e. by exon skipping, intron retention, alternative 5' splice site (5'ss), 3' splice site (3'ss), or polyadenylation usage, lead to remarkable transcriptome and proteome diversity in human tissues. Given its critical biological importance, alternative splicing is tightly regulated in a tissue- and developmental stage-specific manner. The central nervous system and skeletal muscle are amongst the tissues with the highest number of differentially expressed alternative exons, revealing a remarkable degree of transcriptome complexity. It is therefore not surprising that splicing mis-regulation is causally associated with a myriad of neuromuscular diseases, including but not limited to amyotrophic lateral sclerosis (ALS), spinal muscular atrophy (SMA), Duchenne muscular dystrophy (DMD), and myotonic dystrophy type 1 and 2 (DM1, DM2). A gene's transcript diversity has since become an integral and an important consideration for drug design, development and therapy. In this review, we will discuss transcript diversity in the context of neuromuscular diseases and current approaches to address splicing mis-regulation.

OsMYB7 determines leaf angle at the late developmental stage of lamina joints in rice.

Leaf angle shapes plant architecture, allowing for optimal light interception to maximize photosynthesis and yield, and therefore is a crucial agronomic trait. Here, we show that the rice (Oryza sativa L.) R2R3-type MYB transcription factor OsMYB7 determines leaf angle in a developmental stage-specific manner. OsMYB7-overexpressing lines produced wide-angled leaves and osmyb7 knockout mutants exhibited erect leaves. This phenotype was restricted to the lamina joints at the late developmental stage. In agreement with these observations, OsMYB7 was preferentially expressed in the lamina joints of post-mature leaves. Since OsMYB7 homologs are transcriptional repressors of lignin biosynthesis, we examined whether OsMYB7 might inhibit thickening ofsecondary cell walls. Although OsMYB7 repressed lignin biosynthesis, it enhanced thickening of sclerenchyma cell walls by elevating cellulose contents at the lamina joints. Furthermore, we found that OsMYB7 affects endogenous auxin levels in lamina joints, and the adaxial cells of lamina joints in OsMYB7-overexpressing lines and osmyb7 knockout mutants exhibited enhanced and reduced elongation, respectively, compared to the wild type. These results suggest that OsMYB7 promotes leaf inclination partially through decreasing free auxin levels and promoting cell elongation at the adaxial side of lamina joints.

Functional evaluation of the insulin/insulin-like growth factor signaling pathway in determination of wing polyphenism in pea aphid.

Wing polyphenism is a common phenomenon that plays key roles in environmental adaptation of insects. Insulin/insulin-like growth factor signaling (IIS) pathway is a highly conserved pathway in regulation of metabolism, development, and growth in metazoans. It has been reported that IIS is required for switching of wing morph in brown planthopper via regulating the development of the wing pad. However, it remains elusive whether and how IIS pathway regulates transgenerational wing dimorphism in aphid. In this study, we found that pairing and solitary treatments can induce pea aphids to produce high and low percentage winged offspring, respectively. The expression level of ILP5 (insulin-like peptide 5) in maternal head was significantly higher upon solitary treatment in comparison with pairing, while silencing of ILP5 caused no obvious change in the winged offspring ratio. RNA interference-mediated knockdown of FoxO (Forkhead transcription factor subgroup O) in stage 20 embryos significantly increased the winged offspring ratio. The results of pharmacological and quantitative polymerase chain reaction experiments showed that the embryonic insulin receptors may not be involved in wing polyphenism. Additionally, ILP4 and ILP11 exhibited higher expression levels in 1st wingless offspring than in winged offspring. We demonstrate that FoxO negatively regulates the wing morph development in embryos. ILPs may regulate aphid wing polyphenism in a developmental stage-specific manner. However, the regulation may be not mediated by the canonical IIS pathway. The findings advance our understanding of IIS pathway in insect transgenerational wing polyphenism.

Comparative Transcriptome Analysis Reveals Common and Developmental Stage-Specific Genes That Respond to Low Nitrogen in Maize Leaves.

A growing leaf can be divided into three sections: division zone, elongation zone, and maturation zone. In previous studies, low nitrogen (LN) inhibited maize growth and development, especially leaf growth; however, the gene expression in response to LN in different regions in leaf were not clear. Here, using hydroponics and a transcriptome approach, we systematically analyzed the molecular responses of those zones and differentially expressed genes (DEG) in response to LN supply. Developmental stage-specific genes (SGs) were highly stage-specific and involved in distinct biological processes. SGs from division (SGs–DZ) and elongation zones (SGs–EZ) were more related to developmentally dependent processes, whereas SGs of the maturation zone (SGs–MZ) were more related to metabolic processes. The common genes (CGs) were overrepresented in carbon and N metabolism, suggesting that rebalancing carbon and N metabolism in maize leaves under LN condition was independent of developmental stage. Coexpression modules (CMs) were also constructed in our experiment and a total of eight CMs were detected. Most of SGs–DZ and SGs–EZ were classified into a set termed CM turquoise, which was mainly enriched in ribosome and DNA replication, whereas several genes from SGs–MZ and CGs were clustered into CM blue, which mainly focused on photosynthesis and carbon metabolism. Finally, a comprehensive coexpression network was extracted from CM blue, and several maize CONSTANS-LIKE(ZmCOL) genes seemed to participate in regulating photosynthesis in maize leaves under LN condition in a developmental stage-specific manner. With this study, we uncovered the LN-responsive CGs and SGs that are important for promoting plant growth and development under insufficient nitrogen supply.

The role of circular RNAs in pulmonary hypertension.

Circular RNAs (circRNAs) are endogenous, covalently circularised, non-protein-coding RNAs generated from back-splicing. Most circRNAs are very stable, highly conserved, and expressed in a tissue-, cell- and developmental stage-specific manner. circRNAs play a significant role in various biological processes, such as regulation of gene expression and protein translation via sponging of microRNAs and binding with RNA-binding proteins. circRNAs have become a topic of great interest in research due to their close link with the development of various diseases. Their high stability, conservation and abundance in body fluids make them promising biomarkers for many diseases. A growing body of evidence suggests that aberrant expression of circRNAs and their targets plays a crucial role in pulmonary vascular remodelling and pulmonary arterial hypertension (group 1) as well as other forms (groups 3 and 4) of pulmonary hypertension (PH). Here we discuss the roles and molecular mechanisms of circRNAs in the pathogenesis of pulmonary vascular remodelling and PH. We also highlight the therapeutic and biomarker potential of circRNAs in PH.

Widespread translational control regulates retinal development in mouse.

Retinal development is tightly regulated to ensure the generation of appropriate cell types and the assembly of functional neuronal circuitry. Despite remarkable advances have been made in understanding regulation of gene expression during retinal development, how translational regulation guides retinogenesis is less understood. Here, we conduct a comprehensive translatome and transcriptome survey to the mouse retinogenesis from the embryonic to the adult stages. We discover thousands of genes that have dynamic changes at the translational level and pervasive translational regulation in a developmental stage-specific manner with specific biological functions. We further identify genes whose translational efficiencies are frequently controlled by changing usage in upstream open reading frame during retinal development. These genes are enriched for biological functions highly important to neurons, such as neuron projection organization and microtubule-based protein transport. Surprisingly, we discover hundreds of previously uncharacterized micropeptides, translated from putative long non-coding RNAs and circular RNAs. We validate their protein products in vitro and in vivo and demonstrate their potentials in regulating retinal development. Together, our study presents a rich and complex landscape of translational regulation and provides novel insights into their roles during retinogenesis.

MicroRNA miR-29c regulates RAG1 expression and modulates V(D)J recombination during B cell development.

Recombination activating genes (RAGs), consisting of RAG1 and RAG2, are stringently regulated lymphoid-specific genes, which initiate V(D)J recombination in developing lymphocytes. We report the regulation of RAG1 through a microRNA (miRNA), miR-29c, in a B cell stage-specific manner in mice and humans. Various lines of experimentation, including CRISPR-Cas9 genome editing, demonstrate the target specificity and direct interaction of miR-29c to RAG1. Modulation of miR-29c levels leads to change in V(D)J recombination efficiency in pre-B cells. The miR-29c expression is inversely proportional to RAG1 in a B cell developmental stage-specific manner, and miR-29c null mice exhibit a reduction in mature B cells. A negative correlation of miR-29c and RAG1 levels is also observed in leukemia patients, suggesting the potential use of miR-29c as a biomarker and a therapeutic target. Thus, our results reveal the role of miRNA in the regulation of RAG1 and its relevance in cancer.

Enhancing B-Cell Malignancies-On Repurposing Enhancer Activity towards Cancer.

Simple SummaryB-cell malignancies are a heterogenous group of lymphomas and leukemias and are the 6th most common cancer-related cause of death. Apart from several oncogenes and tumor suppressors involved in their pathogenesis, recently the role of non-coding, regulatory sequences has been implied. Enhancers are DNA elements controlling gene expression to ensure proper cell development and function. However, the activity of enhancers can be redirected, setting cells on the path towards cancer. In this review, we discuss different mechanisms through which enhancers are exploited in malignant B cells. We also highlight the potential of therapeutic targeting of enhancers as a direction for future investigation.B-cell lymphomas and leukemias derive from B cells at various stages of maturation and are the 6th most common cancer-related cause of death. While the role of several oncogenes and tumor suppressors in the pathogenesis of B-cell neoplasms was established, recent research indicated the involvement of non-coding, regulatory sequences. Enhancers are DNA elements controlling gene expression in a cell type- and developmental stage-specific manner. They ensure proper differentiation and maturation of B cells, resulting in production of high affinity antibodies. However, the activity of enhancers can be redirected, setting B cells on the path towards cancer. In this review we discuss different mechanisms through which enhancers are exploited in malignant B cells, from the well-studied translocations juxtaposing oncogenes to immunoglobulin loci, through enhancer dysregulation by sequence variants and mutations, to enhancer hijacking by viruses. We also highlight the potential of therapeutic targeting of enhancers as a direction for future investigation.

Circular RNAs: Emerging Regulators of the Major Signaling Pathways Involved in Cancer Progression.

Simple SummaryCircular RNAs (circRNAs) are single-stranded RNA molecules that form a covalently closed loop structure. They are characterized by distinct features and multifariously implicated in the regulation of both physiological and pathological states. The aberrant expression of circRNAs has been evidenced in various malignancies. Circular transcripts can effectively modulate gene expression. The most prevalent manner through which circRNAs promote cancer development and progression is their interaction with key components of major signaling pathways. In particular, abnormally expressed circRNAs can dictate the crosstalk between signaling cascades. In recent years, there has been great progress regarding circRNA research in the context of cancer progression, and various regulatory axes have been described. As our knowledge of signaling regulation by circRNAs continuously expands, novel therapeutic approaches can be assessed and established, seeking to overcome clinical challenges, such as the treatment of cancer patients with distant metastasis and those who relapse.Signal transduction is an essential process that regulates and coordinates fundamental cellular processes, such as development, immunity, energy metabolism, and apoptosis. Through signaling, cells are capable of perceiving their environment and adjusting to changes, and most signaling cascades ultimately lead to alterations in gene expression. Circular RNAs (circRNAs) constitute an emerging type of endogenous transcripts with regulatory roles and unique properties. They are stable and expressed in a tissue-, cell-, and developmental stage-specific manner, while they are involved in the pathogenesis of several diseases, including cancer. Aberrantly expressed circRNAs can mediate cancer progression through regulation of the activity of major signaling cascades, such as the VEGF, WNT/β-catenin, MAPK, PI3K/AKT, and Notch signaling pathways, as well as by interfering with signaling crosstalk. Deregulated signaling can then function to induce angiogenesis, promote invasion, migration, and metastasis, and, generally, modulate the hallmarks of cancer. In this review article, we summarize the most recently described and intriguing cases of circRNA-mediated signaling regulation that are involved in cancer progression, and discuss the biomarker potential of circRNAs, as well as future therapeutic applications.

The Vesicle‐Mediated Transport Genes, Snap23 , Tmed2 , and Trip10 , are Alternatively Spliced During Striated Muscle Development

The reprogramming of alternative splicing patterns during development is a hallmark of tissue maturation and identity. Heart and skeletal (striated) muscle tissues exhibit the most highly conserved splicing programs, which substantially change during postnatal development. Notably, alterations of these splicing events are associated with severe cardiac and muscular diseases. In striated muscle, a collection of genes encoding membrane trafficking proteins are spliced in a developmental stage-specific manner. However, few splice isoforms have been characterized, and little is known about their functional roles during heart and skeletal muscle development. We hypothesize that coordinated splicing of membrane trafficking genes represents a splicing network, which functions to regulate the transport of cargo that is critical for muscle development and homeostasis. Here, we characterize three proteins involved in vesicle-mediated transport that are alternatively spliced in striated muscle: SNAP23, TMED2, and TRIP10. The synaptosome-associated protein 23 (SNAP23) is a SNARE protein that mediates vesicle fusion with the plasma membrane during exocytosis, the transmembrane emp23 domain-containing protein 2 (TMED2) regulates vesicle budding during secretion, and the thyroid hormone receptor interactor 10 (TRIP10) is involved in endocytosis and membrane tubulation. First, we found that during striated muscle development, the Snap23, Tmed2, and Trip10 pre-mRNAs undergo splicing changes of a single exon. Second, these three splicing transitions are characterized by a shift from short to long isoform expression that are regulated by the RBPs quaking (QKI) and polypyrimidine tract binding protein 1 (PTBP1). Third, depletion of SNAP23 in muscle cells results in reduced cell viability and differentiation, which can be rescued with conditioned media from differentiated cells or by seeding cells on collagen-coated plates. Finally, exclusive expression of the short SNAP23 isoform leads to increased fusion of myoblasts into myotubes that exhibit greater myotube area and a higher nuclei-per-myotube ratio. Taken together, our data suggest that splicing of Snap23 is an important regulator of myogenesis, where SNAP23 isoform expression controls secretion of cargo that is necessary for muscle cell fusion and myotube size. Preliminary studies show that disruption of TMED2 and TRIP10 isoform levels in muscle cells likewise affects differentiation. Elucidating the mechanisms of regulation and the functional consequences of splicing networks will be fundamental to our understanding of muscle development and disease.

Expression Analyses of Mediator Complex Subunit 13-Like: A Responsible Gene for Neurodevelopmental Disorders during Mouse Brain Development

MED13L (mediator complex subunit 13-like) is a component of the mediator complex, which functions as a regulator for gene transcription. Since gene abnormalities in MED13L are responsible for neurodevelopmental disorders, MED13L is presumed to play an essential role in brain development. In this study, we prepared a specific antibody against MED13L, anti-MED13L, and analyzed its expression profile in mouse tissues with focusing on the central nervous system. In Western blotting, MED13L exhibited a tissue-dependent expression profile in the adult mouse and was expressed in a developmental stage-dependent manner in brain. In immunofluorescence analyses, MED13L was at least partially colocalized with pre- and post-synaptic markers, synaptophysin, and PSD95, in primary cultured hippocampal neurons. Immunohistochemical analyses revealed that MED13L was relatively highly expressed in ventricular zone surface of cerebral cortex, and was also located both in the cytoplasm and nucleus of neurons in the cortical plate at embryonic day 14. Then, MED13L showed diffuse cytoplasmic distribution throughout the cerebral cortex at the postnatal day (P) 30. In addition, MED13L appeared to be localized in cell type- and developmental stage-specific manners in the hippocampus and cerebellum. These results suggest that MED13L is involved in the development of the central nervous system and synaptic function.

Embryo Buoyancy and Cell Death Gene Expression During Embryogenesis of Yellow-Tail Kingfish Seriola lalandi.

In pelagic fish, embryo buoyancy is a noteworthy aspect of the reproductive strategy, and is associated with overall quality, survival, and further developmental success. In captivity, the loss of buoyancy of early embryos correlates with high mortality that might be related to massive cell death. Therefore, the aim of this study was to evaluate under captivity conditions the expression of genes related to the apoptosis process during the early embryonic development of the pelagic fish Seriola lalandi, and its relationship to the buoyancy of embryos. The relative expression of bcl2, bax-like, casp9, casp8, and casp3 was evaluated by RT-qPCR and FasL/Fas protein levels by western blot in five development stages of embryos sorted as floating or low-floating. All genes examined were expressed in both floating and low-floating embryos up to 24 h of development. Expression of the pro-apoptotic factors bax, casp9, casp8, and casp3 was higher in low-floating as compared with floating embryos in a developmental stage-specific manner. In contrast, there was no difference in expression of bcl2 between floating and low-floating embryos. Fas protein was detected as a single band in floating embryos without changes in expression throughout development; however, in low-floating embryos, three higher intensity reactive bands were detected in the 24-h embryos. Interestingly, FasL was only detected at 24-h in floating embryos, whereas in low-floating samples this ligand was present at all stages, with a sharp increase as development progressed. Cell death, as evaluated by the terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling assay, was highly increased in low-floating embryos as compared to floating embryos throughout all developmental stages, with the highest levels observed during the gastrula stage and at 24 h. The results of this study suggest that an increase in cell death, probably associated with the intrinsic and extrinsic apoptosis pathways, is present in low-floating embryos that might explain their lower developmental potential under captivity conditions.

Epigenetic inactivation of ERF reactivates γ-globin expression in β-thalassemia

The fetal-to-adult hemoglobin switch is regulated in a developmental stage-specific manner and reactivation of fetal hemoglobin (HbF) has therapeutic implications for treatment of β-thalassemia and sickle cell anemia, two major global health problems. Although significant progress has been made in our understanding of the molecular mechanism of the fetal-to-adult hemoglobin switch, the mechanism of epigenetic regulation of HbF silencing remains to be fully defined. Here, we performed whole-genome bisulfite sequencing and RNA sequencing analysis of the bone marrow-derived GYPA+ erythroid cells from β-thalassemia-affected individuals with widely varying levels of HbF groups (HbF ≥ 95th percentile or HbF ≤ 5th percentile) to screen epigenetic modulators of HbF and phenotypic diversity of β-thalassemia. We identified an ETS2 repressor factor encoded by ERF, whose promoter hypermethylation and mRNA downregulation are associated with high HbF levels in β-thalassemia. We further observed that hypermethylation of the ERF promoter mediated by enrichment of DNMT3A leads to demethylation of γ-globin genes and attenuation of binding of ERF on the HBG promoter and eventually re-activation of HbF in β-thalassemia. We demonstrated that ERF depletion markedly increased HbF production in human CD34+ erythroid progenitor cells, HUDEP-2 cell lines, and transplanted NCG-Kit-V831M mice. ERF represses γ-globin expression by directly binding to two consensus motifs regulating γ-globin gene expression. Importantly, ERF depletion did not affect maturation of erythroid cells. Identification of alterations in DNA methylation of ERF as a modulator of HbF synthesis opens up therapeutic targets for β-hemoglobinopathies.

Alternative Splicing: Expanding the Landscape of Cancer Biomarkers and Therapeutics.

Alternative splicing (AS) is a critical post-transcriptional regulatory mechanism used by more than 95% of transcribed human genes and responsible for structural transcript variation and proteome diversity. In the past decade, genome-wide transcriptome sequencing has revealed that AS is tightly regulated in a tissue- and developmental stage-specific manner, and also frequently dysregulated in multiple human cancer types. It is currently recognized that splicing defects, including genetic alterations in the spliced gene, altered expression of both core components or regulators of the precursor messenger RNA (pre-mRNA) splicing machinery, or both, are major drivers of tumorigenesis. Hence, in this review we provide an overview of our current understanding of splicing alterations in cancer, and emphasize the need to further explore the cancer-specific splicing programs in order to obtain new insights in oncology. Furthermore, we also discuss the recent advances in the identification of dysregulated splicing signatures on a genome-wide scale and their potential use as biomarkers. Finally, we highlight the therapeutic opportunities arising from dysregulated splicing and summarize the current approaches to therapeutically target AS in cancer.

The role of circular RNAs in therapy resistance of patients with solid tumors.

Circular RNAs (circRNAs) are a type of single-stranded RNA molecules forming a covalently closed, continuous structure, lacking 5'-3' polarity and polyadenylated tails. Recent advances in high-throughput sequencing technologies have revealed that these molecules are abundant, resistant to degradation and often expressed in a tissue- or developmental stage-specific manner. circRNAs are produced by back-splicing circularization of primary transcripts and exhibit a variety of functions, including regulation of transcription, translation and cellular localization. This review focuses on differentially expressed circRNAs conferring therapy resistance or sensitivity of solid tumors, such as carcinomas, sarcomas and lymphomas. Deregulated circRNAs can participate in the development of resistance to treatment by modulating regulatory pathways and cellular processes, including the mitogen-activated protein kinase pathway, epithelial-mesenchymal transition, apoptosis and autophagy.

Conformational dependence of integrin-binding peptides derived from homologous loop regions in the laminin α chains.

Laminin α chains (α1-α5 chains) are expressed in a tissue- and developmental stage-specific manner and have diverse chain-specific biological functions. Especially, laminin globular (LG) modules (LG1-LG5) located at the C-terminus of the α chains play a critical role in the biological activities of laminins. Each LG module is composed of a 14-stranded β-sheet (A-N) sandwich structure. We previously screened cell attachment activity of the loop regions between the E and F strands in the LG modules using 17 homologous peptides (EF peptides) and found that four active EF peptides bind to integrin α2β1. One of the four peptides, G4EF1 demonstrated improved cell attachment activity when cyclized. Here, we focused on the remaining three integrin α2β1-binding EF peptides (G5EF1, G3EF3, and G5EF5) and analyzed the relationship between their peptide conformation and cell attachment activity. First, we determined their active core sequences and found that G5EF1z (IGLEIVDGKVLFHVNN), G3EF3z (LLVTLEDGHIALST), and G5EF5z (KVLTEQVL) are the core sequences. Cyclic peptides of the core sequences (cycloG5EF1z, cycloG3EF3z, and cycloG5EF5z) enhanced integrin-mediated cell adhesion activity compared with their linear peptides. The results indicated that cell adhesion activity of the integrin α2β1-binding EF peptides is conformation dependent and that the loop structure is critical for their activity. This suggests that conformation of the loop regions plays an important role for the activities of the LG modules.

Exploration of Susceptible Genes with Clustered Regularly Interspaced Short Palindromic Repeats–Tissue-Specific Knockout (CRISPR-TSKO) to Enhance Host Resistance

Susceptible (S) genes are those plant genes that facilitate pathogen infection and disease. The loss of function of these genes primarily interrupts the growth and development of invading pathogens and thus makes plants resistant. The S-gene-targeted resistance may produce durable immunity in plants. Because, S gene-based resistance is derived from the inactivation of a host factor required for the survival of a pathogen in the host. To bypass the S gene-based resistance, a parasitic pathogen must evolve and develop the same or similar functions provided naturally by its host factors, which is far more difficult or even may be impossible. However, it is critical to identify and target the appropriate S gene(s) aiming to gain resistant capacity against a particular disease, because S genes may be pathogen-specific in many cases. The clustered regularly interspaced short palindromic repeats (CRISPR) technology has shown great potential in manipulating S genes in plants. The CRISPR-TSKO (CRISPR-based tissue-specific knock-out) tool kit can provide an understanding of the exact function of an individual gene in a tissue and developmental stage-specific manner while also producing a heritable mutant allele. In this review, candidate S genes have been summarized for CRISPR-TSKO mediated tissue-specific gene knockdown to enhance host resistance.