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1.
Am J Hum Genet ; 93(2): 346-56, 2013 Aug 08.
Artículo en Inglés | MEDLINE | ID: mdl-23891471

RESUMEN

Primary ciliary dyskinesia (PCD) is a ciliopathy characterized by airway disease, infertility, and laterality defects, often caused by dual loss of the inner dynein arms (IDAs) and outer dynein arms (ODAs), which power cilia and flagella beating. Using whole-exome and candidate-gene Sanger resequencing in PCD-affected families afflicted with combined IDA and ODA defects, we found that 6/38 (16%) carried biallelic mutations in the conserved zinc-finger gene BLU (ZMYND10). ZMYND10 mutations conferred dynein-arm loss seen at the ultrastructural and immunofluorescence level and complete cilia immotility, except in hypomorphic p.Val16Gly (c.47T>G) homozygote individuals, whose cilia retained a stiff and slowed beat. In mice, Zmynd10 mRNA is restricted to regions containing motile cilia. In a Drosophila model of PCD, Zmynd10 is exclusively expressed in cells with motile cilia: chordotonal sensory neurons and sperm. In these cells, P-element-mediated gene silencing caused IDA and ODA defects, proprioception deficits, and sterility due to immotile sperm. Drosophila Zmynd10 with an equivalent c.47T>G (p.Val16Gly) missense change rescued mutant male sterility less than the wild-type did. Tagged Drosophila ZMYND10 is localized primarily to the cytoplasm, and human ZMYND10 interacts with LRRC6, another cytoplasmically localized protein altered in PCD. Using a fly model of PCD, we conclude that ZMYND10 is a cytoplasmic protein required for IDA and ODA assembly and that its variants cause ciliary dysmotility and PCD with laterality defects.


Asunto(s)
Cilios/genética , Dineínas/genética , Infertilidad Masculina/genética , Síndrome de Kartagener/genética , Proteínas/genética , Sistema Respiratorio/metabolismo , Proteínas Supresoras de Tumor/genética , Animales , Axonema/genética , Axonema/metabolismo , Axonema/patología , Cilios/metabolismo , Cilios/patología , Proteínas del Citoesqueleto , Drosophila melanogaster/genética , Drosophila melanogaster/metabolismo , Dineínas/metabolismo , Exoma , Femenino , Regulación de la Expresión Génica , Secuenciación de Nucleótidos de Alto Rendimiento , Humanos , Infertilidad Masculina/metabolismo , Infertilidad Masculina/patología , Síndrome de Kartagener/metabolismo , Síndrome de Kartagener/patología , Masculino , Ratones , Mutación , Linaje , Estructura Terciaria de Proteína , Proteínas/metabolismo , Sistema Respiratorio/patología , Proteínas Supresoras de Tumor/metabolismo
2.
PLoS Biol ; 9(1): e1000568, 2011 Jan 04.
Artículo en Inglés | MEDLINE | ID: mdl-21283833

RESUMEN

In neurogenesis, neural cell fate specification is generally triggered by proneural transcription factors. Whilst the role of proneural factors in fate specification is well studied, the link between neural specification and the cellular pathways that ultimately must be activated to construct specialised neurons is usually obscure. High-resolution temporal profiling of gene expression reveals the events downstream of atonal proneural gene function during the development of Drosophila chordotonal (mechanosensory) neurons. Among other findings, this reveals the onset of expression of genes required for construction of the ciliary dendrite, a key specialisation of mechanosensory neurons. We determine that atonal activates this cellular differentiation pathway in several ways. Firstly, atonal directly regulates Rfx, a well-known highly conserved ciliogenesis transcriptional regulator. Unexpectedly, differences in Rfx regulation by proneural factors may underlie variations in ciliary dendrite specialisation in different sensory neuronal lineages. In contrast, fd3F encodes a novel forkhead family transcription factor that is exclusively expressed in differentiating chordotonal neurons. fd3F regulates genes required for specialized aspects of chordotonal dendrite physiology. In addition to these intermediate transcriptional regulators, we show that atonal directly regulates a novel gene, dilatory, that is directly associated with ciliogenesis during neuronal differentiation. Our analysis demonstrates how early cell fate specification factors can regulate structural and physiological differentiation of neuronal cell types. It also suggests a model for how subtype differentiation in different neuronal lineages may be regulated by different proneural factors. In addition, it provides a paradigm for how transcriptional regulation may modulate the ciliogenesis pathway to give rise to structurally and functionally specialised ciliary dendrites.


Asunto(s)
Drosophila/metabolismo , Perfilación de la Expresión Génica , Células Receptoras Sensoriales/fisiología , Regulación hacia Arriba , Animales , Factores de Transcripción con Motivo Hélice-Asa-Hélice Básico/genética , Factores de Transcripción con Motivo Hélice-Asa-Hélice Básico/metabolismo , Diferenciación Celular , Línea Celular , Cilios/genética , Proteínas de Unión al ADN/genética , Proteínas de Unión al ADN/metabolismo , Drosophila/embriología , Drosophila/crecimiento & desarrollo , Proteínas de Drosophila/genética , Proteínas de Drosophila/metabolismo , Factores de Transcripción Forkhead/genética , Factores de Transcripción Forkhead/metabolismo , Genes Reporteros , Larva/crecimiento & desarrollo , Larva/metabolismo , Proteínas del Tejido Nervioso/genética , Proteínas del Tejido Nervioso/metabolismo , Factores de Transcripción del Factor Regulador X , Células Receptoras Sensoriales/ultraestructura , Factores de Transcripción/genética , Factores de Transcripción/metabolismo
3.
BMC Dev Biol ; 10: 34, 2010 Mar 26.
Artículo en Inglés | MEDLINE | ID: mdl-20346138

RESUMEN

BACKGROUND: bHLH transcription factors play many roles in neural development. cousin of atonal (cato) encodes one such factor that is expressed widely in the developing sensory nervous system of Drosophila. However, nothing definitive was known of its function owing to the lack of specific mutations. RESULTS: We characterised the expression pattern of cato in detail using newly raised antibodies and GFP reporter gene constructs. Expression is predominantly in sensory lineages that depend on the atonal and amos proneural genes. In lineages that depend on the scute proneural gene, cato is expressed later and seems to be particularly associated with the type II neurons. Consistent with this, we find evidence that cato is a direct target gene of Atonal and Amos, but not of Scute. We generated two specific mutations of cato. Mutant embryos show several defects in chordotonal sensory lineages, most notably the duplication of the sensory neuron, which appears to be caused by an extra cell division. In addition, we show that cato is required to form the single chordotonal organ that persists in atonal mutant embryos. CONCLUSIONS: We conclude that although widely expressed in the developing PNS, cato is expressed and regulated very differently in different sensory lineages. Mutant phenotypes correlate with cato's major expression in the chordotonal sensory lineage. In these cells, we propose that it plays roles in sense organ precursor maintenance and/or identity, and in controlling the number of cell divisions in the neuronal branch of the lineage arising from these precursors.


Asunto(s)
Drosophila melanogaster/embriología , Drosophila melanogaster/metabolismo , Animales , Factores de Transcripción con Motivo Hélice-Asa-Hélice Básico/genética , Factores de Transcripción con Motivo Hélice-Asa-Hélice Básico/metabolismo , Proteínas de Drosophila/genética , Proteínas de Drosophila/metabolismo , Proteínas del Tejido Nervioso/metabolismo , Neurogénesis , Sistema Nervioso Periférico/metabolismo , Células Receptoras Sensoriales/metabolismo
4.
Dev Cell ; 7(5): 687-96, 2004 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-15525530

RESUMEN

In Drosophila, commitment of a cell to a sense organ precursor (SOP) fate requires bHLH proneural transcription factor upregulation, a process that depends in most cases on the interplay of proneural gene autoregulation and inhibitory Notch signaling. A subset of SOPs are selected by a recruitment pathway involving EGFR signaling to ectodermal cells expressing the proneural gene atonal. We show that EGFR signaling drives recruitment by directly facilitating atonal autoregulation. Pointed, the transcription factor that mediates EGFR signaling, and Atonal protein itself bind cooperatively to adjacent conserved binding sites in an atonal enhancer. Recruitment is therefore contingent on the combined presence of Atonal protein (providing competence) and EGFR signaling (triggering recruitment). Thus, autoregulation is the nodal control point targeted by signaling. This exemplifies a simple and general mechanism for regulating the transition from competence to cell fate commitment whereby a cell signal directly targets the autoregulation of a selector gene.


Asunto(s)
Drosophila/embriología , Receptores ErbB/metabolismo , Regulación del Desarrollo de la Expresión Génica , Órganos de los Sentidos/embriología , Transducción de Señal , Animales , Factores de Transcripción con Motivo Hélice-Asa-Hélice Básico , Sitios de Unión , Proteínas de Unión al ADN/metabolismo , Drosophila/genética , Proteínas de Drosophila , Ensayo de Cambio de Movilidad Electroforética , Elementos de Facilitación Genéticos , Glutatión Transferasa/metabolismo , Proteínas Fluorescentes Verdes/metabolismo , Inmunohistoquímica , Proteínas de la Membrana/metabolismo , Modelos Biológicos , Modelos Moleculares , Proteínas del Tejido Nervioso , Proteínas Proto-Oncogénicas/metabolismo , Receptores Notch , Proteínas Recombinantes de Fusión/metabolismo , Factores de Transcripción/metabolismo , Regulación hacia Arriba
5.
Mol Cell Biol ; 24(21): 9517-26, 2004 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-15485919

RESUMEN

For a particular functional family of basic helix-loop-helix (bHLH) transcription factors, there is ample evidence that different factors regulate different target genes but little idea of how these different target genes are distinguished. We investigated the contribution of DNA binding site differences to the specificities of two functionally related proneural bHLH transcription factors required for the genesis of Drosophila sense organ precursors (Atonal and Scute). We show that the proneural target gene, Bearded, is regulated by both Scute and Atonal via distinct E-box consensus binding sites. By comparing with other Ato-dependent enhancer sequences, we define an Ato-specific binding consensus that differs from the previously defined Scute-specific E-box consensus, thereby defining distinct E(Ato) and E(Sc) sites. These E-box variants are crucial for function. First, tandem repeats of 20-bp sequences containing E(Ato) and E(Sc) sites are sufficient to confer Atonal- and Scute-specific expression patterns, respectively, on a reporter gene in vivo. Second, interchanging E(Ato) and E(Sc) sites within enhancers almost abolishes enhancer activity. While the latter finding shows that enhancer context is also important in defining how proneural proteins interact with these sites, it is clear that differential utilization of DNA binding sites underlies proneural protein specificity.


Asunto(s)
Proteínas de Unión al ADN/metabolismo , Proteínas de Drosophila/metabolismo , Drosophila/genética , Elementos E-Box/genética , Regulación del Desarrollo de la Expresión Génica , Sistema Nervioso/metabolismo , Neuronas/metabolismo , Factores de Transcripción/metabolismo , Región de Flanqueo 3'/genética , Región de Flanqueo 5'/genética , Animales , Secuencia de Bases , Factores de Transcripción con Motivo Hélice-Asa-Hélice Básico , ADN/genética , ADN/metabolismo , Proteínas de Unión al ADN/química , Proteínas de Unión al ADN/genética , Drosophila/citología , Drosophila/embriología , Drosophila/metabolismo , Proteínas de Drosophila/química , Proteínas de Drosophila/genética , Proteínas del Tejido Nervioso , Sistema Nervioso/citología , Sistema Nervioso/embriología , Factores de Transcripción/química , Factores de Transcripción/genética
6.
BMC Dev Biol ; 6: 53, 2006 Nov 09.
Artículo en Inglés | MEDLINE | ID: mdl-17094800

RESUMEN

BACKGROUND: The regulation of proneural gene expression is an important aspect of neurogenesis. In the study of the Drosophila proneural genes, scute and atonal, several themes have emerged that contribute to our understanding of the mechanism of neurogenesis. First, spatial complexity in proneural expression results from regulation by arrays of enhancer elements. Secondly, regulation of proneural gene expression occurs in distinct temporal phases, which tend to be under the control of separate enhancers. Thirdly, the later phase of proneural expression often relies on positive autoregulation. The control of these phases and the transition between them appear to be central to the mechanism of neurogenesis. We present the first investigation of the regulation of the proneural gene, amos. RESULTS: Amos protein expression has a complex pattern and shows temporally distinct phases, in common with previously characterised proneural genes. GFP reporter gene constructs were used to demonstrate that amos has an array of enhancer elements up- and downstream of the gene, which are required for different locations of amos expression. However, unlike other proneural genes, there is no evidence for separable enhancers for the different temporal phases of amos expression. Using mutant analysis and site-directed mutagenesis of potential Amos binding sites, we find no evidence for positive autoregulation as an important part of amos control during neurogenesis. CONCLUSION: For amos, as for other proneural genes, a complex expression pattern results from the sum of a number of simpler sub-patterns driven by specific enhancers. There is, however, no apparent separation of enhancers for distinct temporal phases of expression, and this correlates with a lack of positive autoregulation. For scute and atonal, both these features are thought to be important in the mechanism of neurogenesis. Despite similarities in function and expression between the Drosophila proneural genes, amos is regulated in a fundamentally different way from scute and atonal.


Asunto(s)
Proteínas de Drosophila/genética , Regulación del Desarrollo de la Expresión Génica , Factores de Crecimiento Nervioso/genética , Neuronas/citología , Factores de Transcripción con Motivo Hélice-Asa-Hélice Básico/genética , Factores de Transcripción con Motivo Hélice-Asa-Hélice Básico/fisiología , Sitios de Unión , Proteínas de Unión al ADN/genética , Proteínas de Unión al ADN/fisiología , Proteínas de Drosophila/fisiología , Mutagénesis Sitio-Dirigida , Factores de Crecimiento Nervioso/fisiología , Proteínas del Tejido Nervioso/genética , Proteínas del Tejido Nervioso/fisiología , Factores de Transcripción/genética , Factores de Transcripción/fisiología
7.
Genetics ; 195(1): 147-58, 2013 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-23821599

RESUMEN

Drosophila telomeres are elongated by the transposition of telomere-specific retrotransposons rather than telomerase activity. Proximal to the terminal transposon array, Drosophila chromosomes contain several kilobases of a complex satellite DNA termed telomere-associated sequences (TASs). Reporter genes inserted into or next to the TAS are silenced through a mechanism called telomere position effect (TPE). TPE is reminiscent of the position effect variegation (PEV) induced by Drosophila constitutive heterochromatin. However, most genes that modulate PEV have no effect on TPE, and systematic searches for TPE modifiers have so far identified only a few dominant suppressors. Surprisingly, only a few of the genes required to prevent telomere fusion have been tested for their effect on TPE. Here, we show that with the exception of the effete (eff; also called UbcD1) mutant alleles, none of the tested mutations at the other telomere fusion genes affects TPE. We also found that mutations in eff, which encodes a class I ubiquitin-conjugating enzyme, act as suppressors of PEV. Thus, eff is one of the rare genes that can modulate both TPE and PEV. Immunolocalization experiments showed that Eff is a major constituent of polytene chromosomes. Eff is enriched at several euchromatic bands and interbands, the TAS regions, and the chromocenter. Our results suggest that Eff associates with different types of chromatin affecting their abilities to regulate gene expression.


Asunto(s)
Efectos de la Posición Cromosómica , Proteínas de Drosophila/genética , Drosophila/genética , Heterocromatina/genética , Telómero/genética , Enzimas Ubiquitina-Conjugadoras/genética , Animales , Drosophila/enzimología , Drosophila/metabolismo , Proteínas de Drosophila/metabolismo , Heterocromatina/metabolismo , Mutación , Cromosomas Politénicos/genética , Cromosomas Politénicos/metabolismo , Telómero/metabolismo , Proteínas de Unión a Telómeros/genética , Proteínas de Unión a Telómeros/metabolismo , Enzimas Ubiquitina-Conjugadoras/metabolismo
8.
Dev Cell ; 22(6): 1221-33, 2012 Jun 12.
Artículo en Inglés | MEDLINE | ID: mdl-22698283

RESUMEN

Cilia have evolved hugely diverse structures and functions to participate in a wide variety of developmental and physiological processes. Ciliary specialization requires differences in gene expression, but few transcription factors are known to regulate this, and their molecular function is unclear. Here, we show that the Drosophila Forkhead box (Fox) gene, fd3F, is required for specialization of the mechanosensory cilium of chordotonal (Ch) neurons. fd3F regulates genes for Ch-specific axonemal dyneins and TRPV ion channels, which are required for sensory transduction, and retrograde transport genes, which are required to differentiate their distinct motile and sensory ciliary zones. fd3F is reminiscent of vertebrate Foxj1, a motile cilia regulator, but fd3F regulates motility genes as part of a broader sensory regulation program. Fd3F cooperates with the pan-ciliary transcription factor, Rfx, to regulate its targets directly. This illuminates pathways involved in ciliary specialization and the molecular mechanism of transcription factors that regulate them.


Asunto(s)
Proteínas de Unión al ADN/metabolismo , Proteínas de Drosophila/metabolismo , Factores de Transcripción Forkhead/metabolismo , Regulación de la Expresión Génica , Mecanotransducción Celular/fisiología , Factores de Transcripción/metabolismo , Animales , Diferenciación Celular/fisiología , Cilios/genética , Cilios/metabolismo , Proteínas de Drosophila/genética , Drosophila melanogaster/genética , Drosophila melanogaster/crecimiento & desarrollo , Drosophila melanogaster/metabolismo , Factores de Transcripción Forkhead/genética , Neurogénesis/genética , Neurogénesis/fisiología , Factores de Transcripción del Factor Regulador X
9.
Fly (Austin) ; 5(4): 322-6, 2011.
Artículo en Inglés | MEDLINE | ID: mdl-21558799

RESUMEN

Much of developmental biology is concerned with the processes by which cells become committed to particular fates in a regulated fashion, whereas cell biology addresses, among other things, the variety of differentiated forms and functions that cells can acquire. One open question is how the regulators of the former process lead to attainment of the latter. 'High-level' regulators of cell fate specification include the proneural factors, which drive cells to commit as precursors in the sensory nervous system. Recent research has concentrated on the gene expression events downstream of proneural factor function. Here we summarise this research and describe our own research that has provided clear links between a proneural factor, atonal, and the cell biological programme of ciliogenesis, which is a central aspect of sensory neuron differentiation.


Asunto(s)
Factores de Transcripción con Motivo Hélice-Asa-Hélice Básico/fisiología , Diferenciación Celular , Drosophila/citología , Proteínas del Tejido Nervioso/fisiología , Animales , Factores de Transcripción con Motivo Hélice-Asa-Hélice Básico/metabolismo , Cilios/genética , Cilios/metabolismo , Drosophila/genética , Proteínas de Drosophila , Modelos Genéticos , Proteínas del Tejido Nervioso/metabolismo , Células Receptoras Sensoriales/citología , Transcriptoma
10.
Development ; 130(19): 4683-93, 2003 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-12925594

RESUMEN

Proneural genes encode basic-helix-loop-helix (bHLH) transcription factors required for neural precursor specification. Recently amos was identified as a new candidate Drosophila proneural gene related to atonal. Having isolated the first specific amos loss-of-function mutations, we show definitively that amos is required to specify the precursors of two classes of olfactory sensilla. Unlike other known proneural mutations, a novel characteristic of amos loss of function is the appearance of ectopic sensory bristles in addition to loss of olfactory sensilla, owing to the inappropriate function of scute. This supports a model of inhibitory interactions between proneural genes, whereby ato-like genes (amos and ato) must suppress sensory bristle fate as well as promote alternative sense organ subtypes.


Asunto(s)
Proteínas de Drosophila , Drosophila melanogaster/embriología , Morfogénesis/fisiología , Factores de Crecimiento Nervioso/genética , Factores de Crecimiento Nervioso/metabolismo , Neuronas Receptoras Olfatorias/fisiología , Animales , Factores de Transcripción con Motivo Hélice-Asa-Hélice Básico , Linaje de la Célula , Proteínas de Unión al ADN/genética , Proteínas de Unión al ADN/metabolismo , Drosophila melanogaster/anatomía & histología , Drosophila melanogaster/genética , Estructuras Embrionarias/anatomía & histología , Estructuras Embrionarias/fisiología , Regulación del Desarrollo de la Expresión Génica , Secuencias Hélice-Asa-Hélice , Hibridación in Situ , Mecanorreceptores/citología , Mecanorreceptores/fisiología , Mutación , Proteínas del Tejido Nervioso , Neuronas Receptoras Olfatorias/citología
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