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Skeletal muscle development is spotlighted in mammals since it closely relates to animal health and economic benefits to the breeding industry. Researchers have successfully unveiled many regulatory factors and mechanisms involving myogenesis. However, the effect of N6-methyladenosine (m6A) modification, especially demethylase and its regulated genes, on muscle development remains to be further explored. Here, we found that the typical demethylase FTO (fat mass- and obesity-associated protein) was highly enriched in goats' longissimus dorsi (LD) muscles. In addition, the level of m6A modification on transcripts was negatively regulated by FTO during the proliferation of goat skeletal muscle satellite cells (MuSCs). Moreover, a deficiency of FTO in MuSCs significantly retarded their proliferation and promoted the expression of dystrophin-associated protein 1 (DAG1). m6A modifications of DAG1 mRNA were efficiently altered by FTO. Intriguingly, the results of DAG1 levels and its m6A enrichment from FB23-2 (FTO demethylase inhibitor)-treated cells were consistent with those of the FTO knockdown, indicating that the regulation of FTO on DAG1 depended on m6A modification. Further experiments showed that interfering FTO improved m6A modification at site DAG1-122, recognized by Insulin-like growth factor 2 mRNA-binding protein 1 (IGF2BP1) and consequently stabilized DAG1 transcripts. Our study suggests that FTO promotes the proliferation of MuSCs by regulating the expression of DAG1 through m6A modification. This will extend our knowledge of the m6A-related mechanism of skeletal muscle development in animals. [ABSTRACT FROM AUTHOR]

Previous studies have uncovered the key role of circular RNAs (circRNAs) in various diseases, including cancer. However, the growth‐inhibitory effects of circRNAs on esophageal squamous cell carcinoma (ESCC) have not been completely elucidated. This study characterized a newly identified circRNA derived from exons 9–13 of TNRC6B (named circ‐TNRC6B). The expression of circ‐TNRC6B in ESCC tissues was markedly downregulated when compared to that in non‐tumor tissues. In 53 ESCC cases, circ‐TNRC6B expression was negatively correlated with the T stage. Multivariate Cox regression analysis showed that circ‐TNRC6B upregulation was an independent protective factor for ESCC patients' prognosis. Overexpression and knockdown functional experiments demonstrated that circ‐TNRC6B inhibited ESCC cell proliferation, migration, and invasion. RNA immunoprecipitation and dual‐luciferase reporter assays demonstrated that circ‐TNRC6B sponges oncogenic miR‐452‐5p to upregulate the expression and activity of DAG1. Treatment with miR‐452‐5p inhibitor partially reversed the circ‐TNRC6B‐induced changes in the biological behavior of ESCC cells. These findings demonstrated that circ‐TNRC6B exerts a tumor‐suppressing effect in ESCC through the miR‐452‐5p/DAG1 axis. Thus, circ‐TNRC6B is a potential prognostic biomarker for the clinical management of ESCC.

Previous studies have uncovered the key role of circular RNAs (circRNAs) in various diseases, including cancer. However, the growth‐inhibitory effects of circRNAs on esophageal squamous cell carcinoma (ESCC) have not been completely elucidated. This study characterized a newly identified circRNA derived from exons 9–13 of TNRC6B (named circ‐TNRC6B). The expression of circ‐TNRC6B in ESCC tissues was markedly downregulated when compared to that in non‐tumor tissues. In 53 ESCC cases, circ‐TNRC6B expression was negatively correlated with the T stage. Multivariate Cox regression analysis showed that circ‐TNRC6B upregulation was an independent protective factor for ESCC patients' prognosis. Overexpression and knockdown functional experiments demonstrated that circ‐TNRC6B inhibited ESCC cell proliferation, migration, and invasion. RNA immunoprecipitation and dual‐luciferase reporter assays demonstrated that circ‐TNRC6B sponges oncogenic miR‐452‐5p to upregulate the expression and activity of DAG1. Treatment with miR‐452‐5p inhibitor partially reversed the circ‐TNRC6B‐induced changes in the biological behavior of ESCC cells. These findings demonstrated that circ‐TNRC6B exerts a tumor‐suppressing effect in ESCC through the miR‐452‐5p/DAG1 axis. Thus, circ‐TNRC6B is a potential prognostic biomarker for the clinical management of ESCC. [ABSTRACT FROM AUTHOR]

Objectives To elaborate the imaging phenotype associated with a homozygous c.743C > del frameshift mutation in DAG1 leading to complete absence of both α- and β-dystroglycan previously reported in a consanguineous Israeli-Arab family. Methods We analyzed prenatal and postnatal imaging data of patients from a consanguineous Israeli-Arab kindred harboring the DAG1 mutation. Results The imaging studies (fetal ultrasound, CT scan and postnatal MRI) demonstrated: flat cortex (abnormally thick with irregular pebbled cortical-white matter border on MRI), hydrocephalus, scattered small periventricular heterotopia and subependymal hemorrhages and calcifications, z-shaped brainstem, and in addition an occipital encephalocele, vermian agenesis, and an elongated and thick tectum (tectocerebellar dysraphia). Conclusions The novel association of cobblestone malformation with tectocerebellar dysraphia as part of WWS is characteristic of the homozygous c.743C > del frameshift mutation in the DAG1 gene. [ABSTRACT FROM AUTHOR]

Background: In seeds, the transition from dormancy to germination is regulated by abscisic acid (ABA) and gibberellins (GAs), and involves chromatin remodelling. Particularly, the repressive mark H3K27 trimethylation (H3K27me3) has been shown to target many master regulators of this transition. DAG1 (DOF AFFECTING GERMINATION1), is a negative regulator of seed germination in Arabidopsis, and directly represses the GA biosynthetic gene GA3ox1 (gibberellin 3-β-dioxygenase 1). We set to investigate the role of DAG1 in seed dormancy and maturation with respect to epigenetic and hormonal control. Results: We show that DAG1 expression is controlled at the epigenetic level through the H3K27me3 mark during the seed-to-seedling transition, and that DAG1 directly represses also the ABA catabolic gene CYP707A2; consistently, the ABA level is lower while the GA level is higher in dag1 mutant seeds. Furthermore, both DAG1 expression and protein stability are controlled by GAs. Conclusions: Our results point to DAG1 as a key player in the control of the developmental switch between seed dormancy and germination. [ABSTRACT FROM AUTHOR]

Background: The transcription factor DOF AFFECTING GERMINATION1 (DAG1) is a repressor of the light-mediated seed germination process. DAG1 acts downstream PHYTOCHROME INTERACTING FACTOR3-LIKE 5 (PIL5), the master repressor, and negatively regulates gibberellin biosynthesis by directly repressing the biosynthetic gene AtGA3ox1. The Dof protein DOF AFFECTING GERMINATION (DAG2) shares a high degree of aminoacidic identity with DAG1. While DAG1 inactivation considerably increases the germination capability of seeds, the dag2 mutant has seeds with a germination potential substantially lower than the wild-type, indicating that these factors may play opposite roles in seed germination. Results: We show here that DAG2 expression is positively regulated by environmental factors triggering germination, whereas its expression is repressed by PIL5 and DAG1; by Chromatin Immuno Precipitation (ChIP) analysis we prove that DAG1 directly regulates DAG2. In addition, we show that Red light significantly reduces germination of dag2 mutant seeds. Conclusions: In agreement with the seed germination phenotype of the dag2 mutant previously published, the present data prove that DAG2 is a positive regulator of the light-mediated seed germination process, and particularly reveal that this protein plays its main role downstream of PIL5 and DAG1 in the phytochrome B (phyB)-mediated pathway. [ABSTRACT FROM AUTHOR]

Background The transcription factor DOF AFFECTING GERMINATION1 (DAG1) is a repressor of seed germination acting downstream of the master repressor PHYTOCROME INTERACTING FACTOR3-LIKE 5 (PIL5). Among others, PIL5 induces the expression of the genes encoding the two DELLA proteins GA INSENSITIVE 1 (GAI) and REPRESSOR OF ga1-3 (RGA). Results Based on the properties of gai-t6 and rga28 mutant seeds, we show here that the absence of RGA severely increases dormancy, while lack of GAI only partially compensates RGA inactivation. In addition, the germination properties of the dag1rga28 double mutant are different from those of the dag1 and rga28 single mutants, suggesting that RGA and DAG1 act in independent branches of the PIL5-controlled germination pathway. Surprisingly, the dag1gai-t6 double mutant proved embryo-lethal, suggesting an unexpected involvement of (a possible complex between) DAG1 and GAI in embryo development. Conclusions Rather than overlapping functions as previously suggested, we show that RGA and GAI play distinct roles in seed germination, and that GAI interacts with DAG1 in embryo development. [ABSTRACT FROM AUTHOR]

Defects in dystroglycan post-translational modification result in congenital muscular dystrophy with or without additional eye and brain involvement, are referred to as secondary dystroglycanopathies and have been associated with mutations in 11 different genes encoding glycosyltransferases or associated proteins. However, only one patient with a mutation in the dystroglycan encoding gene DAG1 itself has been described before. We here report a homozygous novel DAG1 missense mutation c.2006G>T predicted to result in the amino acid substitution p.Cys669Phe in the β-subunit of dystroglycan in two Libyan siblings. The affected girls presented with a severe muscle-eye-brain disease-like phenotype with distinct additional findings of macrocephaly and extended bilateral multicystic white matter disease, overlapping with the cerebral findings in patients with megalencephalic leucoencephalopathy with subcortical cysts. This novel clinical phenotype observed in our patients further expands the clinical spectrum of dystroglycanopathies and suggests a role of DAG1 not only for dystroglycanopathies but also for some forms of more extensive and multicystic leucodystrophy. [ABSTRACT FROM AUTHOR]

Background: Deregulation of cell-matrix interactions is considered an important factor in malignant transformation. Dystroglycan forms the interface between the basement membrane and the cell membrane in epithelia by its two subunits, α- and β-dystroglycan. Aberrant expression of dystroglycan has been observed in various human cancers. Here we assessed the expression of dystroglycan in pancreatic ductal adenocarcinoma (PDAC) and analyzed its association with clinical parameters. Methods: mRNA levels of dystroglycan were determined by real-time quantitative PCR in tissue samples from 60 patients with PDAC, from 48 patients with CP, and from 18 healthy donors. Furthermore, pancreatic cancer specimens of 53 patients were analyzed by immunohistochemistry using specific α- and β-dystroglycan antibodies. The staining was semiquantitatively evaluated and correlated to patient survival using the Kaplan-Meier method. Results: On the mRNA level, dystroglycan was down-regulated in PDAC compared with the normal pancreas. In normal pancreatic tissues, α- and β-dystroglycans were mainly expressed on the basolateral cell membrane of acinar and ductal cells, while islet cells showed a cytoplasmatic staining. In contrast, in PDAC tissues, this membrane staining pattern was lost and replaced by a cytoplasmatic staining, suggesting impairments in the membrane translocation of both dystroglycans. Semiquantitative analysis revealed a significant inverse correlation of α- (but not β-) dystroglycan staining and postoperative survival (P =0.039). Conclusion: Reduced expression and altered localization of dystroglycan is common in PDAC, potentially contributing to the aggressive behavior of this disease. [Copyright &y& Elsevier]

Light regulates Arabidopsis seed germination through the phyB / PIL5 (PHYTOCHROME INTERACTING FACTOR 3-LIKE 5) transduction pathway, and we have previously shown that the Dof transcription factor DOF AFFECTING GERMINATION1 (DAG1) is a component of this pathway. By means of microarray analysis of dag1 and wild type developing siliques, we identified the EARLY LIGHT-INDUCED PROTEIN1 and 2 (ELIP1 and ELIP2) genes among those deregulated in the loss-of-function dag1 mutant. We analysed seed germination of elip single and double mutants, of elip dag1 double mutants as well as of elip1 elip2 dag1 triple mutant under different environmental conditions. We show that ELIP1 and ELIP2 are involved in opposite ways in the control of this developmental process, in particular under abiotic (light, temperature, salt) stress conditions. [ABSTRACT FROM AUTHOR]