Genes

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Open AccessReview

Ups and Downs: Mechanisms of Repeat Instability in the Fragile X-Related Disorders

by Xiao-Nan Zhao and Karen Usdin

Genes 2016, 7(9), 70; https://doi.org/10.3390/genes7090070 - 21 Sep 2016

Cited by 12 | Viewed by 6449

The Fragile X-related disorders (FXDs) are a group of clinical conditions resulting from the expansion of a CGG/CCG-repeat tract in exon 1 of the Fragile X mental retardation 1 (FMR1) gene. While expansions of the repeat tract predominate, contractions are also seen with [...] Read more.

The Fragile X-related disorders (FXDs) are a group of clinical conditions resulting from the expansion of a CGG/CCG-repeat tract in exon 1 of the Fragile X mental retardation 1 (FMR1) gene. While expansions of the repeat tract predominate, contractions are also seen with the net result being that individuals can show extensive repeat length heterogeneity in different tissues. The mechanisms responsible for expansion and contraction are still not well understood. This review will discuss what is known about these processes and current evidence that supports a model in which expansion arises from the interaction of components of the base excision repair, mismatch repair and transcription coupled repair pathways. Full article

(This article belongs to the Special Issue Fragile X Syndrome)

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Open AccessArticle

Regulation of BLM Nucleolar Localization

by Larissa Tangeman, Michael A. McIlhatton, Patrick Grierson, Joanna Groden and Samir Acharya

Genes 2016, 7(9), 69; https://doi.org/10.3390/genes7090069 - 21 Sep 2016

Cited by 10 | Viewed by 6973

Abstract

Defects in coordinated ribosomal RNA (rRNA) transcription in the nucleolus cause cellular and organismal growth deficiencies. Bloom’s syndrome, an autosomal recessive human disorder caused by mutated recQ-like helicase BLM, presents with growth defects suggestive of underlying defects in rRNA transcription. Our previous studies [...] Read more.

Defects in coordinated ribosomal RNA (rRNA) transcription in the nucleolus cause cellular and organismal growth deficiencies. Bloom’s syndrome, an autosomal recessive human disorder caused by mutated recQ-like helicase BLM, presents with growth defects suggestive of underlying defects in rRNA transcription. Our previous studies showed that BLM facilitates rRNA transcription and interacts with RNA polymerase I and topoisomerase I (TOP1) in the nucleolus. The mechanisms regulating localization of BLM to the nucleolus are unknown. In this study, we identify the TOP1-interaction region of BLM by co-immunoprecipitation of in vitro transcribed and translated BLM segments and show that this region includes the highly conserved nuclear localization sequence (NLS) of BLM. Biochemical and nucleolar co-localization studies using site-specific mutants show that two serines within the NLS (S1342 and S1345) are critical for nucleolar localization of BLM but do not affect the functional interaction of BLM with TOP1. Mutagenesis of both serines to aspartic acid (phospho-mimetic), but not alanine (phospho-dead), results in approximately 80% reduction in nucleolar localization of BLM while retaining the biochemical functions and nuclear localization of BLM. Our studies suggest a role for this region in regulating nucleolar localization of BLM via modification of the two serines within the NLS. Full article

(This article belongs to the Special Issue Replication and Transcription Associated DNA Repair)

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Open AccessCase Report

Molecular Inconsistencies in a Fragile X Male with Early Onset Ataxia

by Yun Tae Hwang, Tracy Dudding, Solange Mabel Aliaga, Marta Arpone, David Francis, Xin Li, Howard Robert Slater, Carolyn Rogers, Lesley Bretherton, Desirée Du Sart, Robert Heard and David Eugeny Godler

Genes 2016, 7(9), 68; https://doi.org/10.3390/genes7090068 - 21 Sep 2016

Cited by 8 | Viewed by 5446

Abstract

Mosaicism for FMR1 premutation (PM: 55–199 CGG)/full mutation (FM: >200 CGG) alleles or the presence of unmethylated FM (UFM) have been associated with a less severe fragile X syndrome (FXS) phenotype and fragile X associated tremor/ataxia syndrome (FXTAS)—a late onset neurodegenerative disorder. We [...] Read more.

Mosaicism for FMR1 premutation (PM: 55–199 CGG)/full mutation (FM: >200 CGG) alleles or the presence of unmethylated FM (UFM) have been associated with a less severe fragile X syndrome (FXS) phenotype and fragile X associated tremor/ataxia syndrome (FXTAS)—a late onset neurodegenerative disorder. We describe a 38 year old male carrying a 100% methylated FM detected with Southern blot (SB), which is consistent with complete silencing of FMR1 and a diagnosis of fragile X syndrome. However, his formal cognitive scores were not at the most severe end of the FXS phenotype and he displayed tremor and ataxic gait. With the association of UFM with FXTAS, we speculated that his ataxia might be related to an undetected proportion of UFM alleles. Such UFM alleles were confirmed by more sensitive PCR based methylation testing showing FM methylation between 60% and 70% in blood, buccal, and saliva samples and real-time PCR analysis showing incomplete silencing of FMR1. While he did not meet diagnostic criteria for FXTAS based on MRI findings, the underlying cause of his ataxia may be related to UFM alleles not detected by SB, and follow-up clinical and molecular assessment are justified if his symptoms worsen. Full article

(This article belongs to the Special Issue Fragile X Syndrome)

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Open AccessReview

DNA Polymerase θ: A Unique Multifunctional End-Joining Machine

by Samuel J. Black, Ekaterina Kashkina, Tatiana Kent and Richard T. Pomerantz

Genes 2016, 7(9), 67; https://doi.org/10.3390/genes7090067 - 21 Sep 2016

Cited by 67 | Viewed by 12589

Abstract

The gene encoding DNA polymerase θ (Polθ) was discovered over ten years ago as having a role in suppressing genome instability in mammalian cells. Studies have now clearly documented an essential function for this unique A-family polymerase in the double-strand break (DSB) repair [...] Read more.

The gene encoding DNA polymerase θ (Polθ) was discovered over ten years ago as having a role in suppressing genome instability in mammalian cells. Studies have now clearly documented an essential function for this unique A-family polymerase in the double-strand break (DSB) repair pathway alternative end-joining (alt-EJ), also known as microhomology-mediated end-joining (MMEJ), in metazoans. Biochemical and cellular studies show that Polθ exhibits a unique ability to perform alt-EJ and during this process the polymerase generates insertion mutations due to its robust terminal transferase activity which involves template-dependent and independent modes of DNA synthesis. Intriguingly, the POLQ gene also encodes for a conserved superfamily 2 Hel308-type ATP-dependent helicase domain which likely assists in alt-EJ and was reported to suppress homologous recombination (HR) via its anti-recombinase activity. Here, we review our current knowledge of Polθ-mediated end-joining, the specific activities of the polymerase and helicase domains, and put into perspective how this multifunctional enzyme promotes alt-EJ repair of DSBs formed during S and G2 cell cycle phases. Full article

(This article belongs to the Special Issue Replication and Transcription Associated DNA Repair)

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Open AccessReview

The Role of ATRX in the Alternative Lengthening of Telomeres (ALT) Phenotype

by João P. Amorim, Gustavo Santos, João Vinagre and Paula Soares

Genes 2016, 7(9), 66; https://doi.org/10.3390/genes7090066 - 19 Sep 2016

Cited by 69 | Viewed by 11233

Abstract

Telomeres are responsible for protecting chromosome ends in order to prevent the loss of coding DNA. Their maintenance is required for achieving immortality by neoplastic cells and can occur by upregulation of the telomerase enzyme or through a homologous recombination-associated process, the alternative [...] Read more.

Telomeres are responsible for protecting chromosome ends in order to prevent the loss of coding DNA. Their maintenance is required for achieving immortality by neoplastic cells and can occur by upregulation of the telomerase enzyme or through a homologous recombination-associated process, the alternative lengthening of telomeres (ALT). The precise mechanisms that govern the activation of ALT or telomerase in tumor cells are not fully understood, although cellular origin may favor one of the other mechanisms that have been found thus far in mutual exclusivity. Specific mutational events influence ALT activation and maintenance: a unifying frequent feature of tumors that acquire this phenotype are the recurrent mutations of the Alpha Thalassemia/Mental Retardation Syndrome X-Linked (ATRX) or Death-Domain Associated Protein (DAXX) genes. This review summarizes the established criteria about this phenotype: its prevalence, theoretical molecular mechanisms and relation with ATRX, DAXX and other proteins (directly or indirectly interacting and resulting in the ALT phenotype). Full article

(This article belongs to the Section Human Genomics and Genetic Diseases)

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Open AccessArticle

Eight Mutations of Three Genes (EDA, EDAR, and WNT10A) Identified in Seven Hypohidrotic Ectodermal Dysplasia Patients

by Binghui Zeng, Xue Xiao, Sijie Li, Hui Lu, Jiaxuan Lu, Ling Zhu, Dongsheng Yu and Wei Zhao

Genes 2016, 7(9), 65; https://doi.org/10.3390/genes7090065 - 19 Sep 2016

Cited by 24 | Viewed by 8561

Abstract

Hypohidrotic ectodermal dysplasia (HED) is characterized by abnormal development of the teeth, hair, and sweat glands. Ectodysplasin A (EDA), Ectodysplasin A receptor (EDAR), and EDAR-associated death domain (EDARADD) are candidate genes for HED, but the relationship between [...] Read more.

Hypohidrotic ectodermal dysplasia (HED) is characterized by abnormal development of the teeth, hair, and sweat glands. Ectodysplasin A (EDA), Ectodysplasin A receptor (EDAR), and EDAR-associated death domain (EDARADD) are candidate genes for HED, but the relationship between WNT10A and HED has not yet been validated. In this study, we included patients who presented at least two of the three ectodermal dysplasia features. The four genes were analyzed in seven HED patients by PCR and Sanger sequencing. Five EDA and one EDAR heterozygous mutations were identified in families 1–6. Two WNT10A heterozygous mutations were identified in family 7 as a compound heterozygote. c.662G>A (p.Gly221Asp) in EDA and c.354T>G (p.Tyr118*) in WNT10A are novel mutations. Bioinformatics analyses results confirmed the pathogenicity of the two novel mutations. In family 7, we also identified two single-nucleotide polymorphisms (SNPs) that were predicted to affect the splicing of EDAR. Analysis of the patient’s total RNA revealed normal splicing of EDAR. This ascertained that the compound heterozygous WNT10A mutations are the genetic defects that led to the onset of HED. Our data revealed the genetic basis of seven HED patients and expended the mutational spectrum. Interestingly, we confirmed WNT10A as a candidate gene of HED and we propose WNT10A to be tested in EDA-negative HED patients. Full article

(This article belongs to the Section Human Genomics and Genetic Diseases)

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Open AccessReview

Telomerase Regulation from Beginning to the End

by Deanna Elise MacNeil, Hélène Jeanne Bensoussan and Chantal Autexier

Genes 2016, 7(9), 64; https://doi.org/10.3390/genes7090064 - 14 Sep 2016

Cited by 66 | Viewed by 9874

Abstract

The vast body of literature regarding human telomere maintenance is a true testament to the importance of understanding telomere regulation in both normal and diseased states. In this review, our goal was simple: tell the telomerase story from the biogenesis of its parts [...] Read more.

The vast body of literature regarding human telomere maintenance is a true testament to the importance of understanding telomere regulation in both normal and diseased states. In this review, our goal was simple: tell the telomerase story from the biogenesis of its parts to its maturity as a complex and function at its site of action, emphasizing new developments and how they contribute to the foundational knowledge of telomerase and telomere biology. Full article

(This article belongs to the Special Issue Telomerase Activity in Human Cells)

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Open AccessReview

Reappearance from Obscurity: Mammalian Rad52 in Homologous Recombination

by Kritika Hanamshet, Olga M. Mazina and Alexander V. Mazin

Genes 2016, 7(9), 63; https://doi.org/10.3390/genes7090063 - 14 Sep 2016

Cited by 61 | Viewed by 14520

Abstract

Homologous recombination (HR) plays an important role in maintaining genomic integrity. It is responsible for repair of the most harmful DNA lesions, DNA double-strand breaks and inter-strand DNA cross-links. HR function is also essential for proper segregation of homologous chromosomes in meiosis, maintenance [...] Read more.

Homologous recombination (HR) plays an important role in maintaining genomic integrity. It is responsible for repair of the most harmful DNA lesions, DNA double-strand breaks and inter-strand DNA cross-links. HR function is also essential for proper segregation of homologous chromosomes in meiosis, maintenance of telomeres, and resolving stalled replication forks. Defects in HR often lead to genetic diseases and cancer. Rad52 is one of the key HR proteins, which is evolutionarily conserved from yeast to humans. In yeast, Rad52 is important for most HR events; Rad52 mutations disrupt repair of DNA double-strand breaks and targeted DNA integration. Surprisingly, in mammals, Rad52 knockouts showed no significant DNA repair or recombination phenotype. However, recent work demonstrated that mutations in human RAD52 are synthetically lethal with mutations in several other HR proteins including BRCA1 and BRCA2. These new findings indicate an important backup role for Rad52, which complements the main HR mechanism in mammals. In this review, we focus on the Rad52 activities and functions in HR and the possibility of using human RAD52 as therapeutic target in BRCA1 and BRCA2-deficient familial breast cancer and ovarian cancer. Full article

(This article belongs to the Special Issue Replication and Transcription Associated DNA Repair)

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Open AccessReview

Mechanisms and Physiological Roles of the CBL-CIPK Networking System in Arabidopsis thaliana

by Jingjing Mao, S. M. Nuruzzaman Manik, Sujuan Shi, Jiangtao Chao, Yirong Jin, Qian Wang and Haobao Liu

Genes 2016, 7(9), 62; https://doi.org/10.3390/genes7090062 - 8 Sep 2016

Cited by 92 | Viewed by 11163

Abstract

Calcineurin B-like protein (CBL)-CBL-interacting protein kinase (CIPK) network is one of the vital regulatory mechanisms which decode calcium signals triggered by environmental stresses. Although the complicated regulation mechanisms and some novel functions of CBL-CIPK signaling network in plants need to be further elucidated, [...] Read more.

Calcineurin B-like protein (CBL)-CBL-interacting protein kinase (CIPK) network is one of the vital regulatory mechanisms which decode calcium signals triggered by environmental stresses. Although the complicated regulation mechanisms and some novel functions of CBL-CIPK signaling network in plants need to be further elucidated, numerous advances have been made in its roles involved in the abiotic stresses. This review chiefly introduces the progresses about protein interaction, classification and expression pattern of different CBLs and CIPKs in Arabidopsis thaliana, summarizes the physiological roles of CBL-CIPK pathway while pointing out some new research ideas in the future, and finally presents some unique perspectives for the further study. The review might provide new insights into the functional characterization of CBL-CIPK pathway in Arabidopsis, and contribute to a deeper understanding of CBL-CIPK network in other plants or stresses. Full article

(This article belongs to the Section Molecular Genetics and Genomics)

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Open AccessReview

Telomerase Activation in Hematological Malignancies

by Joana Ropio, Jean-Philippe Merlio, Paula Soares and Edith Chevret

Genes 2016, 7(9), 61; https://doi.org/10.3390/genes7090061 - 7 Sep 2016

Cited by 22 | Viewed by 5578

Abstract

Telomerase expression and telomere maintenance are critical for cell proliferation and survival, and they play important roles in development and cancer, including hematological malignancies. Transcriptional regulation of the rate-limiting subunit of human telomerase reverse transcriptase gen (hTERT) is a complex process, and [...] Read more.

Telomerase expression and telomere maintenance are critical for cell proliferation and survival, and they play important roles in development and cancer, including hematological malignancies. Transcriptional regulation of the rate-limiting subunit of human telomerase reverse transcriptase gen (hTERT) is a complex process, and unveiling the mechanisms behind its reactivation is an important step for the development of diagnostic and therapeutic applications. Here, we review the main mechanisms of telomerase activation and the associated hematologic malignancies. Full article

(This article belongs to the Special Issue Telomerase Activity in Human Cells)

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Open AccessReview

The Telomere/Telomerase System in Chronic Inflammatory Diseases. Cause or Effect?

by Vasileios Kordinas, Anastasios Ioannidis and Stylianos Chatzipanagiotou

Genes 2016, 7(9), 60; https://doi.org/10.3390/genes7090060 - 3 Sep 2016

Cited by 107 | Viewed by 13082

Abstract

Telomeres are specialized nucleoprotein structures located at the end of linear chromosomes and telomerase is the enzyme responsible for telomere elongation. Telomerase activity is a key component of many cancer cells responsible for rapid cell division but it has also been found by [...] Read more.

Telomeres are specialized nucleoprotein structures located at the end of linear chromosomes and telomerase is the enzyme responsible for telomere elongation. Telomerase activity is a key component of many cancer cells responsible for rapid cell division but it has also been found by many laboratories around the world that telomere/telomerase biology is dysfunctional in many other chronic conditions as well. These conditions are characterized by chronic inflammation, a situation mostly overlooked by physicians regarding patient treatment. Among others, these conditions include diabetes, renal failure, chronic obstructive pulmonary disease, etc. Since researchers have in many cases identified the association between telomerase and inflammation but there are still many missing links regarding this correlation, the latest findings about this phenomenon will be discussed by reviewing the literature. Our focus will be describing telomere/telomerase status in chronic diseases under the prism of inflammation, reporting molecular findings where available and proposing possible future approaches. Full article

(This article belongs to the Special Issue Telomerase Activity in Human Cells)

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Open AccessArticle

Towards a Better Molecular Diagnosis of FMR1-Related Disorders—A Multiyear Experience from a Reference Lab

by Sylwia Olimpia Rzońca, Monika Gos, Daniel Szopa, Danuta Sielska-Rotblum, Aleksandra Landowska, Agnieszka Szpecht-Potocka, Michał Milewski, Jolanta Czekajska, Anna Abramowicz, Ewa Obersztyn, Dorota Maciejko, Tadeusz Mazurczak and Jerzy Bal

Genes 2016, 7(9), 59; https://doi.org/10.3390/genes7090059 - 2 Sep 2016

Cited by 4 | Viewed by 5704

Abstract

The article summarizes over 20 years of experience of a reference lab in fragile X mental retardation 1 gene (FMR1) molecular analysis in the molecular diagnosis of fragile X spectrum disorders. This includes fragile X syndrome (FXS), fragile X-associated primary ovarian [...] Read more.

The article summarizes over 20 years of experience of a reference lab in fragile X mental retardation 1 gene (FMR1) molecular analysis in the molecular diagnosis of fragile X spectrum disorders. This includes fragile X syndrome (FXS), fragile X-associated primary ovarian insufficiency (FXPOI) and fragile X-associated tremor/ataxia syndrome (FXTAS), which are three different clinical conditions with the same molecular background. They are all associated with an expansion of CGG repeats in the 5′UTR of FMR1 gene. Until 2016, the FMR1 gene was tested in 9185 individuals with the pre-screening PCR, supplemented with Southern blot analysis and/or Triplet Repeat Primed PCR based method. This approach allowed us to confirm the diagnosis of FXS, FXPOI FXTAS in 636/9131 (6.96%), 4/43 (9.3%) and 3/11 (27.3%) of the studied cases, respectively. Moreover, the FXS carrier status was established in 389 individuals. The technical aspect of the molecular analysis is very important in diagnosis of FXS-related disorders. The new methods were subsequently implemented in our laboratory. This allowed the significance of the Southern blot technique to be decreased until its complete withdrawal. Our experience points out the necessity of implementation of the GeneScan based methods to simplify the testing procedure as well as to obtain more information for the patient, especially if TP-PCR based methods are used. Full article

(This article belongs to the Special Issue Fragile X Syndrome)

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Open AccessReview

Telomeres and Telomerase in Cardiovascular Diseases

by Jih-Kai Yeh and Chao-Yung Wang

Genes 2016, 7(9), 58; https://doi.org/10.3390/genes7090058 - 1 Sep 2016

Cited by 144 | Viewed by 17950

Abstract

Telomeres are tandem repeat DNA sequences present at the ends of each eukaryotic chromosome to stabilize the genome structure integrity. Telomere lengths progressively shorten with each cell division. Inflammation and oxidative stress, which are implicated as major mechanisms underlying cardiovascular diseases, increase the [...] Read more.

Telomeres are tandem repeat DNA sequences present at the ends of each eukaryotic chromosome to stabilize the genome structure integrity. Telomere lengths progressively shorten with each cell division. Inflammation and oxidative stress, which are implicated as major mechanisms underlying cardiovascular diseases, increase the rate of telomere shortening and lead to cellular senescence. In clinical studies, cardiovascular risk factors such as smoking, obesity, sedentary lifestyle, and hypertension have been associated with short leukocyte telomere length. In addition, low telomerase activity and short leukocyte telomere length have been observed in atherosclerotic plaque and associated with plaque instability, thus stroke or acute myocardial infarction. The aging myocardium with telomere shortening and accumulation of senescent cells limits the tissue regenerative capacity, contributing to systolic or diastolic heart failure. In addition, patients with ion-channel defects might have genetic imbalance caused by oxidative stress-related accelerated telomere shortening, which may subsequently cause sudden cardiac death. Telomere length can serve as a marker for the biological status of previous cell divisions and DNA damage with inflammation and oxidative stress. It can be integrated into current risk prediction and stratification models for cardiovascular diseases and can be used in precise personalized treatments. In this review, we summarize the current understanding of telomeres and telomerase in the aging process and their association with cardiovascular diseases. In addition, we discuss therapeutic interventions targeting the telomere system in cardiovascular disease treatments. Full article

(This article belongs to the Special Issue Telomerase Activity in Human Cells)

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Open AccessReview

DNA Polymerases λ and β: The Double-Edged Swords of DNA Repair

by Elisa Mentegari, Miroslava Kissova, Laura Bavagnoli, Giovanni Maga and Emmanuele Crespan

Genes 2016, 7(9), 57; https://doi.org/10.3390/genes7090057 - 31 Aug 2016

Cited by 18 | Viewed by 5883

Abstract

DNA is constantly exposed to both endogenous and exogenous damages. More than 10,000 DNA modifications are induced every day in each cell’s genome. Maintenance of the integrity of the genome is accomplished by several DNA repair systems. The core enzymes for these pathways [...] Read more.

DNA is constantly exposed to both endogenous and exogenous damages. More than 10,000 DNA modifications are induced every day in each cell’s genome. Maintenance of the integrity of the genome is accomplished by several DNA repair systems. The core enzymes for these pathways are the DNA polymerases. Out of 17 DNA polymerases present in a mammalian cell, at least 13 are specifically devoted to DNA repair and are often acting in different pathways. DNA polymerases β and λ are involved in base excision repair of modified DNA bases and translesion synthesis past DNA lesions. Polymerase λ also participates in non-homologous end joining of DNA double-strand breaks. However, recent data have revealed that, depending on their relative levels, the cell cycle phase, the ratio between deoxy- and ribo-nucleotide pools and the interaction with particular auxiliary proteins, the repair reactions carried out by these enzymes can be an important source of genetic instability, owing to repair mistakes. This review summarizes the most recent results on the ambivalent properties of these enzymes in limiting or promoting genetic instability in mammalian cells, as well as their potential use as targets for anticancer chemotherapy. Full article

(This article belongs to the Special Issue Replication and Transcription Associated DNA Repair)

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Open AccessArticle

Possible Therapeutic Doses of Cannabinoid Type 1 Receptor Antagonist Reverses Key Alterations in Fragile X Syndrome Mouse Model

by Maria Gomis-González, Arnau Busquets-Garcia, Carlos Matute, Rafael Maldonado, Susana Mato and Andrés Ozaita

Genes 2016, 7(9), 56; https://doi.org/10.3390/genes7090056 - 31 Aug 2016

Cited by 32 | Viewed by 9779

Abstract

Fragile X syndrome (FXS) is the most common monogenetic cause of intellectual disability. The cognitive deficits in the mouse model for this disorder, the Fragile X Mental Retardation 1 (Fmr1) knockout (KO) mouse, have been restored by different pharmacological approaches, among those the [...] Read more.

Fragile X syndrome (FXS) is the most common monogenetic cause of intellectual disability. The cognitive deficits in the mouse model for this disorder, the Fragile X Mental Retardation 1 (Fmr1) knockout (KO) mouse, have been restored by different pharmacological approaches, among those the blockade of cannabinoid type 1 (CB1) receptor. In this regard, our previous study showed that the CB1 receptor antagonist/inverse agonist rimonabant normalized a number of core features in the Fmr1 knockout mouse. Rimonabant was commercialized at high doses for its anti-obesity properties, and withdrawn from the market on the bases of mood-related adverse effects. In this study we show, by using electrophysiological approaches, that low dosages of rimonabant (0.1 mg/kg) manage to normalize metabotropic glutamate receptor dependent long-term depression (mGluR-LTD). In addition, low doses of rimonabant (from 0.01 mg/kg) equally normalized the cognitive deficit in the mouse model of FXS. These doses of rimonabant were from 30 to 300 times lower than those required to reduce body weight in rodents and to presumably produce adverse effects in humans. Furthermore, NESS0327, a CB1 receptor neutral antagonist, was also effective in preventing the novel object-recognition memory deficit in Fmr1 KO mice. These data further support targeting CB1 receptors as a relevant therapy for FXS. Full article

(This article belongs to the Special Issue Fragile X Syndrome)

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Open AccessReview

Targeting the Hippo Signaling Pathway for Tissue Regeneration and Cancer Therapy

by Wen Chun Juan and Wanjin Hong

Genes 2016, 7(9), 55; https://doi.org/10.3390/genes7090055 - 30 Aug 2016

Cited by 64 | Viewed by 19985

Abstract

The Hippo signaling pathway is a highly-conserved developmental pathway that plays an essential role in organ size control, tumor suppression, tissue regeneration and stem cell self-renewal. The YES-associated protein (YAP) and the transcriptional co-activator with PDZ-binding motif (TAZ) are two important transcriptional co-activators [...] Read more.

The Hippo signaling pathway is a highly-conserved developmental pathway that plays an essential role in organ size control, tumor suppression, tissue regeneration and stem cell self-renewal. The YES-associated protein (YAP) and the transcriptional co-activator with PDZ-binding motif (TAZ) are two important transcriptional co-activators that are negatively regulated by the Hippo signaling pathway. By binding to transcription factors, especially the TEA domain transcription factors (TEADs), YAP and TAZ induce the expression of growth-promoting genes, which can promote organ regeneration after injury. Therefore, controlled activation of YAP and TAZ can be useful for regenerative medicine. However, aberrant activation of YAP and TAZ due to deregulation of the Hippo pathway or overexpression of YAP/TAZ and TEADs can promote cancer development. Hence, pharmacological inhibition of YAP and TAZ may be a useful approach to treat tumors with high YAP and/or TAZ activity. In this review, we present the mechanisms regulating the Hippo pathway, the role of the Hippo pathway in tissue repair and cancer, as well as a detailed analysis of the different strategies to target the Hippo signaling pathway and the genes regulated by YAP and TAZ for regenerative medicine and cancer therapy. Full article

(This article belongs to the Special Issue Hippo Signaling Pathway)

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