GATA Family Of Transcription Factors Research Articles

GATAe transcription factor is involved in Bacillus thuringiensis Cry1Ac toxin receptor gene expression inducing toxin susceptibility

The insecticidal Cry toxins produced by Bacillus thuringiensis (Bt) are powerful tools for insect control. Cry toxin receptors such as cadherin (CAD), ABCC2 transporter and alkaline phosphatase (ALP), located on insect midgut cells, are needed for Cry toxicity. Although insect cell lines are useful experimental models for elucidating toxin action mechanism, most of them show low expression of Cry-receptors genes. The GATA transcription factor family plays important roles in regulating development and differentiation of intestine stem cells. Here, we investigated whether GATAs transcription factors are involved in the expression of Cry1Ac-receptors genes, using multiple insect cell lines. Four GATA genes were identified in the transcriptome of the midgut tissue from the lepidopteran larvae Helicoverpa armigera. These HaGATA genes were transiently expressed in three lepidopteran cell lines, Spodoptera frugiperda Sf9, H. armigera QB-Ha-E5 and Trichoplusia ni Hi5. Analysis of transcription activity using transcriptional gene-fusions showed that only H. armigera GATAe (HaGATAe) significantly increased the transcription of CAD, ABCC2 and ALP receptors genes in all insect cell lines. Key DNA regions for HaGATAe regulation were identified in the promoter sequence of these Cry-receptors genes by using promoter deletion mapping. The transient expression of HaGATAe in these cell lines, conferred sensitivity to Cry1Ac toxin, although in Hi5 cells the susceptibility to Cry1Ac was lower than in other two cell lines. High sensitivity to Cry1Ac correlated with simultaneous transcription of ABCC2 and CAD genes in Sf9 and QB-Ha-E5 cells. Our results reveal that HaGATAe enhances transcription of several lepidopteran Cry1Ac receptor genes in cultured insect cells.

Regulation of Morphology, Aflatoxin Production, and Virulence of Aspergillus flavus by the Major Nitrogen Regulatory Gene areA.

Aspergillus flavus is a renowned plant, animal and human pathogen. areA is a global nitrogen regulatory gene of the GATA transcription factor family, shown to be the major nitrogen regulator. In this study, we identified areA in A. flavus and studied its function. The AreA protein contained a signatory zinc finger domain, which is extremely conserved across fungal species. Gene deletion (ΔareA) and over-expression (OE::areA) strains were constructed by homologous recombination to elucidate the role of areA in A. flavus. The ΔareA strain was unable to efficiently utilize secondary nitrogen sources for growth of A. flavus, and it had poorly developed conidiophores, when observed on complete medium, resulting in the production of significantly less conidia than the wild-type strain (WT). Aflatoxin B1 (AFB1) production was reduced in ΔareA compared with the WT strain in most conditions tested, and ΔareA had impaired virulence in peanut seeds. areA also played important roles in the sensitivity of A. flavus to osmotic, cell wall and oxidative stresses. Hence, areA was found to be important for the growth, aflatoxin production and pathogenicity of A. flavus. This work sheds light on the function of areA in the regulation of the nitrogen metabolism of A. flavus, and consequently aims at providing new ways for controlling the crossover pathogen, A. flavus.

GATA2 mutations in myeloid malignancies: Two zinc fingers in many pies

The GATA family of transcription factors are zinc finger (ZF) DNA-binding proteins that regulate transcription during development and cell differentiation. GATA2 plays an essential role in the regulation of hematopoiesis. As a result, mutations in this gene or alterations in its expression level or function have been linked to a variety of human hematologic disorders. In this review, we summarize the findings and developments over the recent years regarding the clinical correlations and functional properties of distinct GATA2 mutations in hematopoietic malignancies, with particular focus on the mutational hotspots in the ZF domains.

Systematic integration of GATA transcription factors and epigenomes via IDEAS paints the regulatory landscape of hematopoietic cells.

Members of the GATA family of transcription factors play key roles in the differentiation of specific cell lineages by regulating the expression of target genes. Three GATA factors play distinct roles in hematopoietic differentiation. In order to better understand how these GATA factors function to regulate genes throughout the genome, we are studying the epigenomic and transcriptional landscapes of hematopoietic cells in a model‐driven, integrative fashion. We have formed the collaborative multi‐lab VISION project to conduct ValIdated Systematic IntegratiON of epigenomic data in mouse and human hematopoiesis. The epigenomic data included nuclease accessibility in chromatin, CTCF occupancy, and histone H3 modifications for 20 cell types covering hematopoietic stem cells, multilineage progenitor cells, and mature cells across the blood cell lineages of mouse. The analysis used the Integrative and Discriminative Epigenome Annotation System (IDEAS), which learns all common combinations of features (epigenetic states) simultaneously in two dimensions—along chromosomes and across cell types. The result is a segmentation that effectively paints the regulatory landscape in readily interpretable views, revealing constitutively active or silent loci as well as the loci specifically induced or repressed in each stage and lineage. Nuclease accessible DNA segments in active chromatin states were designated candidate cis‐regulatory elements in each cell type, providing one of the most comprehensive registries of candidate hematopoietic regulatory elements to date. Applications of VISION resources are illustrated for the regulation of genes encoding GATA1, GATA2, GATA3, and Ikaros. VISION resources are freely available from our website http://usevision.org.

GATA factor transcriptional activity: Insights from genome-wide binding profiles.

The members of the GATA family of transcription factors have homologous zinc fingers and bind to similar sequence motifs. Recent advances in genome-wide technologies and the integration of bioinformatics data have led to a better understanding of how GATA factors regulate gene expression; GATA-factor-induced transcriptional and epigenetic changes have now been analyzed at unprecedented levels of detail. Here, we review the results of genome-wide studies of GATA factor occupancy in human and murine cell lines and primary cells (as determined by chromatin immunoprecipitation sequencing), and then discuss the molecular mechanisms underlying the mediation of transcriptional and epigenetic regulation by GATA factors.

The role of transcription factor GATA6 in lung development and diseases

GATA transcription factors encode a zinc finger DNA binding protein and play an important role in regulating cell proliferation and differentiation.GATA6 is an important member of the GATA transcription factor family, mainly expressed in the tissues and organs derived from endoderm.It is also the most fundamental member of the GATA family located in the airway epithelial cells.It is involved not only in the regulation of normal lung tissue development, but also in the pathogenesis of lung diseases.This review focuses on the role of GATA6 in lung development and some lung diseases. Key words: GATA6; Lung development; Lung disease

The roles and regulation mechanism of transcription factor GATA6 in cardiovascular diseases

The GATA transcription factor family consists of six members, GATA1 through GATA6, which play important roles in the regulation of cell growth and differentiation, cell survival, and maintenance of body functions. Current studies regarding GATA6 transcription factor confirm that GATA6 plays a crucial role in the differentiation, development, and function of the human heart. Genetic mutations of GATA6 are associated with a variety of congenital heart diseases, dysfunction of the cardiac conduction system causing various arrhythmias, coronary artery disease, and dilated and hypertrophic cardiomyopathies. The relationship between GATA6 and the human heart is also impacted by multiple other genes and interactions in the body. In this review, we summarize the research and current knowledge of the GATA6 transcription factor related to the human heart and multiple pathologies which provides understanding of its genetic basis to enable future personalized gene therapy and to promote the development and incorporation of basic research into clinical medicine.

Molecular characterization and expression profiles provide new insights into GATA5 functions in tongue sole (Cynoglossus semilaevis)

GATA5 is a member of the GATA transcription factor family, which serves essential roles in varieties of cellular functions and biological processes. In this study, we have accomplished the molecular cloning, bioinformatic analysis and preliminary function study of C. semilaevis GATA5. The full-length cDNA nucleotide sequence is 1955 bp, with a coding sequence of 1167 bp, which encodes a polypeptide of 388 amino acids. Homology, phylogenetic, gene structure and synteny analysis showed that C. semilaevis GATA5 was highly conserved among vertebrates. Tissue distribution pattern exhibited that C. semilaevis GATA5 was significantly expressed in heart, intestine, liver, kidney and gonad, with a sexual dimorphic feature observed in testis and ovary. Embryonic development expression profiles showed that C. semilaevis GATA5 transcripts increased at the blastula stage, and peaked at the heat-beating period. Strong signals were detected at spermatids of male testis and stage III oocytes of female ovary by ISH. The expression of C. semilaevis GATA5 was regulated by 17α-MT and E2 after hormone stimulation to the ovary. Together, all the results pointed out that GATA5 might play a vital role during gonadal maturation and the reproductive cycle of C. semilaevis. This study lays the foundation for further researches on the sex control breeding in tongue sole.

GATA1 promotes colorectal cancer cell proliferation, migration and invasion via activating AKT signaling pathway.

GATA1, a member of the GATA transcription factor family, was reported to play a role in development and progression of erythroid cells and breast cancer cells. However, the role of GATA1 in colorectal cancer (CRC) is unknown. Here, we demonstrate that GATA1 was upregulated in CRC tissues compared with normal tissues, and predicted poor clinical outcome in CRC. Biological functional analyses showed that GATA1 knockdown decreased CRC cells proliferation, migration and invasion, and regulated the process of epithelial-mesenchymal transition (EMT). Moreover, silencing of GATA1 suppressed colorectal tumor growth in nude mice. Mechanistically, GATA1 overexpression significantly increased the activity of PI3K/AKT signaling pathway in CRC cells. These data provide insight into the important role of GATA1 in CRC progression and suggest that GATA1 is a potential therapeutic target for CRC.

Novel roles for GATAe in growth, maintenance and proliferation of cell populations in the Drosophila renal tubule.

The GATA family of transcription factors is implicated in numerous developmental and physiological processes in metazoans. In Drosophila melanogaster, five different GATA factor genes (pannier, serpent, grain, GATAd and GATAe) have been reported as essential in the development and identity of multiple tissues, including the midgut, heart and brain. Here, we present a novel role for GATAe in the function and homeostasis of the Drosophila renal (Malpighian) tubule. We demonstrate that reduced levels of GATAe gene expression in tubule principal cells induce uncontrolled cell proliferation, resulting in tumorous growth with associated altered expression of apoptotic and carcinogenic key genes. Furthermore, we uncover the involvement of GATAe in the maintenance of stellate cells and migration of renal and nephritic stem cells into the tubule. Our findings of GATAe as a potential master regulator in the events of growth control and cell survival required for the maintenance of the Drosophila renal tubule could provide new insights into the molecular pathways involved in the formation and maintenance of a functional tissue and kidney disease.

Lateral Root Initiation in the Parental Root Meristem of Cucurbits: Old Players in a New Position.

While in most higher plants, including the model system Arabidopsis thaliana, the formation of lateral root primordia is induced in the elongation zone of the parental root, in seven plant families, including Cucurbitaceae, an alternative root branching mechanism is established such that lateral roots are initiated directly in the apical meristem of the parental root. In Arabidopsis, the transcription factor GATA23 and MEMBRANE-ASSOCIATED KINASE REGULATOR4 (MAKR4) are involved in the gene regulatory network of lateral root initiation. Among all marker genes examined, these are the earliest known marker genes up-regulated by auxin during lateral root initiation. In this study, putative functional orthologs of Arabidopsis GATA23 and MAKR4 were identified in cucumber (Cucumis sativus) and squash (Cucurbita pepo). Both cucurbits contained 26 genes encoding GATA family transcription factors and only one MAKR4 gene. Phylogenetic and transcriptional analysis of up-regulation by auxin led to the identification of GATA23 putative functional orthologs in Cucurbitaceae – CpGATA24 and CsGATA24. In squash, CpMAKR4 was up-regulated by naphthylacetic acid (NAA) and, similar to MAKR4 in Arabidopsis, indole-3-butyric acid (IBA). A detailed analysis of the expression pattern of CpGATA24 and CpMAKR4 in squash roots from founder cell specification until emergence of lateral root primordia was carried out using promoter-fluorescent reporter gene fusions and confocal microscopy. Their expression was induced in the protoxylem, and then expanded to founder cells in the pericycle. Thus, while the overall expression pattern of these genes was significantly different from that in Arabidopsis, in founder cells their expression was induced in the same order as in Arabidopsis. Altogether, these findings suggest that in Cucurbitaceae the putative functional orthologs of GATA23 and MAKR4 might play a role in founder cell specification and primordium positioning during lateral root initiation. The role of the protoxylem in auxin transport as a trigger of founder cells specification and lateral root initiation is discussed.

Research progress of relationship between GATA family gene mutations with congenital heart diseases

The GATA transcription factor family is a type of transcription regulatory factors containing zinc finger structure, in which GATA4, GATA5 and GATA6 play a key role in the process of heart development and functional maturity.A large number of studies have confirmed that the GATA transcription factor family is not only involved in the the heart development, but also its mutations are related to the occurrence of human congenital heart diseases(CHD). This article mainly reviews the relationship between GATA family with heart development, and the relationship between GATA family gene mutation with congenital heart diseases. Key words: GATA transcription factor; Congenital heart disease; Gene mutation

GATA-4 regulates neuronal apoptosis after intracerebral hemorrhage via the NF-κB/Bax/Caspase-3 pathway both in vivo and in vitro

GATA-binding protein 4 (GATA-4)，a member of the GATA family of transcription factors, is expressed in the normal brain and participates in the neural inflammatory response and senescence. However, few studies have investigated whether GATA-4 is involved in the brain damage induced by intracerebral hemorrhage (ICH). The aim of this study was to investigate in vivo and in vitro the role of GATA-4 in ICH-induced secondary brain injury (SBI) and its potential underlying mechanisms. A rat model of ICH was established by autologous blood injection in vivo. In vitro, oxidized hemoglobin was applied to mimic the effects of ICH in neuronal culture. The function of GATA-4 and its mechanism of action after ICH were investigated using siRNA-mediated knockdown and plasmid-mediated overexpression techniques combined with immunofluorescence, western blot, and other molecular methods. It was found that the expression of GATA-4 was increased in the brain of rats after ICH, and its phosphorylation also increased correspondingly. Furthermore, knocking down the expression of GATA-4 led to a significant decrease in neurobehavioral scores and neuronal apoptosis, indicating that secondary brain damage was improved. Conversely, the overexpression of GATA-4 aggravated brain damage. Blockade of a critical phosphorylation site on the GATA-4 overexpression plasmid alleviated the exacerbated damage in vitro and in vivo. Moreover, GATA-4 promoted the activation of NF-κB, and increased the expression of Bax, and cysteine aspartate-specific protease 3 (caspase-3) in its cleaved form, causing neuronal apoptosis. In conclusion, the expression of GATA-4 was increased in the brain of rats after ICH. GATA-4 phosphorylation mediates the function of the protein in ICH-induced SBI. Neuronal apoptosis after ICH was mainly induced by NF-κB activation, which was promoted by GATA-4.

Deregulated Expression of Long Non-Coding RNA AC092580.4 in Acute Myeloid Leukemia

Introduction: Acute myeloid leukemia (AML) is a malignant clonal proliferative disease originating from hematopoietic stem cells, characterized by anemia, hemorrhage, infection and organ infiltration. Most of the patients had poor prognosis and the molecular mechanism of AML is not clear. Therefore, it is urgent to find new molecular markers and therapeutic targets for AML. Long noncoding RNAs (lncRNAs) are a class of RNAs, which are longer than 200nt and without the ability of encoding functional proteins [A. Fatica et al., 2014]. Accumulating studies have found that lncRNAs play an important role in the development of hematological tumors, especially in AML [Huang J et al., 2014; Xing C-y et al., 2015]. In order to investigate the mechanism of lncRNAs in AML, we screened the differentially expressed RNAs in 5 AML patients and 5 IDA controls by microarray (GSE103828), and lncRNA AC092580.4 was verified markedly low expressed in AML (fold change=15.25, P= 0.0002). Then, We further explored the relationship between the expression levels of AC092580.4 and the clinical characteristics and prognosis of AML.Methods: Bone marrow (BM) samples from patients with AML and iron deficiency anemia (IDA) were collected and qRT-PCR was performed to verify the expression levels of AC092580.4 in AML patients and controls. The Receiver Operating Characteristic (ROC) was established to analyze whether AC092580.4 could be used as a bio-marker for newly diagnosed AML patients. The clinical data, including age, gender, percentage of blast cells in BM, chromosome and gene abnormalities, risk stratification, white blood cell counts and overall survival were collected. The correlation between the expression levels of AC092580.4 and clinical characteristics were analyzed by SPSS22.0.Results: The expression levels of AC092580.4 in newly diagnosed AML (n=83) was significantly lower (Figure A) than IDA (n=24) (p < 0.0001). The ROC (Figure B) was established and the area under curve was 0.868 (p < 0.001, CI: 0.780 - 0.957), which indicated that AC092580.4 could be used as an effective index to distinguish the newly diagnosed AML from the controls. Clinical data were collected from 83 newly diagnosed AML patients, 67% was the mean value of the percentage of blast cells in BM . It was found that the expression levels of AC092580.4 were significantly different between the high (≥67%) and low(<67%) percentage of blast cells (p=0.001), high white blood cell group (WBC≥100×109/L) and non high white blood cell group (WBC<100×109/L) (p=0.021). There was no significant difference of the expression levels in the patients with favourable, intermediate and adverse according to Diagnosis and management of AML in adults 2017 ELN recommendations from an international expert panel (p=0.328). The overall survival rate (Figure C) analysis showed that AML patients with high expression levels of AC092580.4 have a better prognosis than low expression group (p=0.018), which indicated that AC092580.4 may be used as an effective index to predict prognosis. To explore the mechanism of AC092580.4 in AML, we obtained sequencing data of 151 adult AML patients from The Cancer Genome Atlas (TCGA) (https://cancergenome.nih.gov/abouttcga/). The correlation coefficient between AC092580.4 and coding gene was estimated by Pearson correlation method. The results showed that the correlation coefficient between GATA3 and AC092580.4 (r = 0.679, P <0.05) was the most significant one among 27338 transcripts (Figure D). Therefore, we hypothesize that AC092580.4 may play an important role in the pathogenesis of AML by interacting with GATA3. GATA3 is a transcription factor of GATA family. While promoting the development of Th2 cells, it can also inhibit the Th1 polarization of Th cells, and eventually lead to higher expression of Th2, which may lead to the occurrence of tumor.Conclusions: Our study sheds light on a novel lncRNA AC092580.4 in AML, and provides its possible functional mechanism preliminary. Whether it can be used as a new powerful therapeutic target for AML treatment remains to be further studied. DisclosuresNo relevant conflicts of interest to declare.

Human GATA1 Driven By the Human Μicro LCR/β-Globin Promoter Rescues the Erythroid but Not the Megakaryocytic Phenotype Induced in Mice By the Gata1low Mutation

GATA1 is a member of the GATA family of transcription factors that exerts a concentration/dependent control on the differentiation of erythroid, megakaryocytic (MK), eosinophil and mast cells. Changes of GATA1 content also controls hematopoietic stem/progenitor cell proliferation and commitment. In fact, in addition to X-linked inherited disorders of the erythroid and/or MK lineage, GATA1 mutations are found in inherited and acquired MK leukaemia and myeloproliferative disorders.To study the regulation of the human β-globin locus, the Stamatoyannopoulos laboratory generated transgenic mice carrying human GATA1 driven by the human μLCR coupled with the β-globin promoter (hGATA1) (Li Q et al. PNAS 1997, 18;94:2444). These transgenic mice are born viable with normal phenotype and express hGATA1 at high levels in embryonic and fetal erythroblasts and barely detectable in the adult ones, raising the question whether in adult cells expression of the endogenous Gata1 may suppress the activity of the human μLCR- β-globin promoter.The aim of this study was to determine the effects of Gata1 on the activity of hGATA1 in mice. Since the Gata1null mutation is embryonically lethal, the hypothesis was tested by generating with standard genetic approaches double mutants carrying hGATA1 and the hypomorphic Gata1low mutation, a mutation that strongly reduces expression of Gata1 in adult hematopoietic cells (erythroblasts, MK, hematopoietic progenitors, others). If successful, these experiments would also indirectly assess the extent by which hGATA1 is capable to rescue the complex Gata1low phenotype. Gata1low mice, in fact, are born anemic and thrombocytopenic but recover from their anemia at 1 month by activating extramedullary hematopoiesis in spleen (Vannucchi et al Blood 2001;97:3040). Spleen erythropoiesis is however mostly ineffective since many of the erythroblasts present in this organ are in apoptosis (Tunel+). Gata1low mice remain thrombocytopenic all their life and with age develop myelofibrosis, a phenotype that resemble primary myelofibrosis, the most severe of the Phyladelphia-negative myeloproliferative neoplasms (Vannucchi et al Blood 2002;100:1123). In these mice, hematopoietic stem cells are detected in spleen, and not in bone marrow, and generate bipotent MK/erythroid progenitors (MEP) with a commitment program screwed toward the mast cell lineage and capable to generate in vitro at the single cell basis mast cell lines (Ghinassi et al. Blood 2007;109:1460-71).Double hGATA1Gata1low mutants were easily generated and were not anemic at birth. At 4 months, they expressed normal haematocrit but reduced blood platelet counts (Fig. 1A,B). RT-PCR analyses of prospectively isolated cell populations confermed that the transgene mRNA is barely detectable in cells from single hGATA1 mutants. By contrast, in the double mutants, hGATA1 mRNA was expressed by common myeloid progenitors, its expression increased by 10-fold in MEP, remained at the same levels expressed by MEP in erythroid cells (CD71+/Ter119+) but was barely detectable in MK (CD41+/CD61+). Expression of hGATA1 did not alter the levels of the endogenous Gata1 expressed by these populations that remained low.MEP purified from double hGATA1/Gata1low mice generated in culture more cells (fold increase=250 in Gata1low/hGATA1 cultures vs 50 in single hGATA1 or Gata1low cultures) which were mostly composed by erythroid precursors unable to generate cell lines.By contrast with single Gata1low mutants, by confocal microscopy, GATA1 was readily detectable in erythroid cells from bone marrow and spleen that these cells were not Tunel+ (Fig. 1C), indicating that hGATA1 reduced ineffective erythropoiesis.GATA1 protein remained not detectable in MK from the same tissues (Fig. 1C) and these cells displayed the abnormal morphology characteristic of the retarded maturation of Gata1low MK. Furthermore, double hGATA1/Gata1low mice, as the single Gata1low ones, developed myelofibrosis in bone marrow (by Gomori staining) at 8 months, confirming that myelofibrosis is driven by MK abnormalities.In conclusion, hGATA1 is expressed by adult CMP, MEP and erythroblasts in a genetic Gata1low background rescuing the MEP and erythroid phenotype induced by the hypomorphic mutation. hGATA1 is not expressed and does not rescue the MK phenotype of Gata1low mice, highlighting the specificity of the β-globin promoter for erythroid cells. [Display omitted] DisclosuresNo relevant conflicts of interest to declare.

Short and narrow flag leaf1, a GATA zinc finger domain-containing protein, regulates flag leaf size in rice (Oryza sativa)

BackgroundThe flag leaf of rice (Oryza sativa L.) is an important determinant of plant type characteristics and grain yield. Identification of flag leaf mutants of rice is crucial to elucidate the molecular mechanism of flag-leaf development, and for exploitation of rice germplasm resources.ResultsIn this study, we describe a mutant designated short and narrow flag leaf 1 (snfl1). Histological analysis showed that the length of epidermal cells and number of longitudinal veins were decreased in the flag leaf of the snfl1 mutant. Map-based cloning indicated that a member of the GATA family of transcription factors is a candidate gene for SNFL1. A single-nucleotide transition at the last base in the single intron of snfl1 led to variation in alternative splicing and early termination of translation. Complemented transgenic plants harbouring the candidate SNFL1 gene rescued the snfl1 mutant. Analysis of RT-PCR and the SNFL1 promoter by means of a GUS fusion expression assay showed that abundance of SNFL1 transcripts was higher in the culm, leaf sheath, and root. Expression of the SNFL1-GFP fusion protein in rice protoplasts showed that SNFL1 was localized in nucleus.ConclusionsWe conclude that SNFL1 is an important regulator of leaf development, the identification of which might have important implications for future research on GATA transcription factors.

GATA transcription factors in development and disease

The GATA family of transcription factors is of crucial importance during embryonic development, playing complex and widespread roles in cell fate decisions and tissue morphogenesis. GATA proteins are essential for the development of tissues derived from all three germ layers, including the skin, brain, gonads, liver, hematopoietic, cardiovascular and urogenital systems. The crucial activity of GATA factors is underscored by the fact that inactivating mutations in most GATA members lead to embryonic lethality in mouse models and are often associated with developmental diseases in humans. In this Primer, we discuss the unique and redundant functions of GATA proteins in tissue morphogenesis, with an emphasis on their regulation of lineage specification and early organogenesis.

Variants in cardiac GATA genes associated with bicuspid aortic valve.

Bicuspid aortic valve (BAV) is a heterogeneous and still not fully understood condition, with diverse genetic aetiology and associated phenotypes ranging from aortic stenosis or regurgitation to aneurysm and dissection. Several genes have been associated with the presence of BAV, notably some members of the GATA family of transcription factors that play important roles in cardiac embryogenesis. A case-control study with 122 unrelated and ethnically matched patients with bicuspid and 154 with tricuspid aortic valve was performed. All exons of GATA4, GATA5, and GATA6 genes were sequenced searching for variants. Frequencies were compared and functional effects of rare variants were analysed by informatic prediction tools. Four rare and potentially pathogenic variants were identified in only five sporadic cases: a missense p.Arg202Gln (rs782614097) in GATA5 and three synonymous variants, p.Cys274= (rs55980825) and p.His302= (rs201516339) in GATA4, and p.Asn458= (rs143026087) in GATA6. Minor alleles of p.His302=, p.Arg202Gln and rs3764962 are enriched in BAV patients compared to ExAC database (P=0.01, 0.03, and 0.01 respectively). In addition, a common polymorphism in GATA5 (p.Asp203=, rs41305803) is associated with BAV showing a protective effect in carriers of the minor allele (OR [95%CI]=0.45[0.25-0.81]; P=0.004). This study associates additional genetic variants in GATA4 and GATA5 with BAV, supporting the implication of these genes in the development of this valvulopathy. The discovery of all the genetic factors involved will contribute to a better understanding of the process and, therefore, to detect a genetic predisposition and even to the identification of therapeutic targets.

The molecular genetic background leading to the formation of the human erythroid-specific Xga/CD99 blood groups

AbstractThe Xga and CD99 antigens of the human Xg blood group system show a unique and sex-specific phenotypic relationship. The phenotypic relationship is believed to result from transcriptional coregulation of the XG and CD99 genes, which span the pseudoautosomal boundary of the X and Y chromosomes. However, the molecular genetic background responsible for these blood groups has remained undetermined. During the present investigation, we initially conducted a pilot study aimed at individuals with different Xga/CD99 phenotypes; this used targeted next-generation sequencing of the genomic areas relevant to XG and CD99. This was followed by a large-scale association study that demonstrated a definite association between a single nucleotide polymorphism (SNP) rs311103 and the Xga/CD99 blood groups. The G and C genotypes of SNP rs311103 were associated with the Xg(a+)/CD99H and Xg(a−)/CD99L phenotypes, respectively. The rs311103 genomic region with the G genotype was found to have stronger transcription-enhancing activity by reporter assay, and this occurred specifically with erythroid-lineage cells. Such activity was absent when the same region with the C genotype was investigated. In silico analysis of the polymorphic rs311103 genomic regions revealed that a binding motif for members of the GATA transcription factor family was present in the rs311103[G] region. Follow-up investigations showed that the erythroid GATA1 factor is able to bind specifically to the rs311103[G] region and markedly stimulates the transcriptional activity of the rs311103[G] segment. The present findings identify the genetic basis of the erythroid-specific Xga/CD99 blood group phenotypes and reveal the molecular background of their formation.

Genome-Wide Regulatory Network Mapping of miRNA and Transcription Factors in Banana Roots

MicroRNA (miRNA) are important regulators of gene expression. Plant miRNA have been reported both to target and to be regulated by transcription factors, however, genomic distribution of miRNA, transcription factor targets for miRNA, transcription factor binding sites (TFBS) of miRNA promoters and their regulatory networks have not been systematically mapped in banana. In this study, genome-wide annotation of miRNA in the most recently published banana genome sequence was used to predict miRNA promoter regions and to map TFBS of miRNA genes. A total of 183 mature miRNAs, comprising 144 orthologous miRNA and 39 Musa-specific miRNA were predicted. Following this, banana root degradome data was used to confirm miRNA targets and the transcription factor targets were placed into a predicted network together with their targeting miRNA using cytoscape. Gene ontology of the 20 transcription factors among the predicted miRNA targets, showed predominance for auxin-activated signalling and developmental processes. Profiling of TFBS motifs across miRNA promoter regions showed that binding site motifs for TCP, AP2/ERF, GATA, NF-YB, DOF, B3, bZIP, trihelix, ZF-HD, bHLH and Dehydrin transcription factor families are abundant in the Musa acuminata genome. Finally, we propose a regulatory network for the miRNA families miR156, miR164, miR166, miR171, miR319, miR396, miR528, mac-miR-new14 and mac-miR-new20 and their respective transcription factor targets.