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1.
AJNR Am J Neuroradiol ; 41(1): 86-91, 2020 01.
Artículo en Inglés | MEDLINE | ID: mdl-31806600

RESUMEN

BACKGROUND AND PURPOSE: Parkinson disease is related to neurodegeneration and iron deposition in the substantia nigra pars compacta and nigrosome 1. However, visualization of nigrosome 1 via MR imaging is poor owing to the bilateral asymmetry, regardless of whether it is healthy. We focused on the magic angle and susceptibility effect and evaluated the anatomic slant structure of nigrosome 1 by tilting subjects' heads in the B0 direction. MATERIALS AND METHODS: To investigate the effectiveness of the magic angle, we tilted the volunteers' heads to the right and left in the B0 direction or not at all for evaluating correlations between the degree of head tilting and visualization of the right nigrosome 1 and left nigrosome 1 using 3D spoiled gradient-echo sequences with multiecho acquisitions. We evaluated the susceptibility of nigrosome 1 and the local field using quantitative susceptibility mapping to assess static magnetic field inhomogeneity. RESULTS: The heads tilted to the right and left showed significantly higher contrasts of nigrosome 1 and the substantia nigra pars compacta than the nontilted heads. No significant differences were observed in the visualization and susceptibility between the right nigrosome 1 and left nigrosome 1 for each head tilt. The effect of the magic angle was remarkable in the nontilted heads. This finding was supported by quantitative susceptibility mapping because the anatomic slant structure of nigrosome 1 was coherent between the axis of nigrosome 1 and the magic angle. CONCLUSIONS: The asymmetric visualization of nigrosome 1 is affected by the magic angle and susceptibility. The anatomic slant structure of nigrosome 1 causes these challenges in visualization.


Asunto(s)
Procesamiento de Imagen Asistido por Computador/métodos , Imagen por Resonancia Magnética/métodos , Sustancia Negra/diagnóstico por imagen , Adulto , Femenino , Humanos , Masculino , Enfermedad de Parkinson , Adulto Joven
2.
Mol Biol Cell ; 11(9): 3205-17, 2000 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-10982411

RESUMEN

Schizosaccharomyces pombe ste11 encodes a high-mobility group family transcriptional activator that is pivotal in sexual development. Transcription of ste11 is induced by starvation of nutrients via a decrease of the cAMP-dependent protein kinase (PKA) activity. Here we report the identification of a novel transcription factor, Rst2p, that directly regulates ste11 expression. Cells in which the rst2 gene was disrupted expressed ste11 poorly and were sterile, and this sterility could be suppressed by artificial expression of ste11. Disruption of rst2 suppressed hypermating and hypersporulation in the PKA-null mutant, whereas overexpression of rst2 induced sexual development in the PKA-activated mutant. Cloning analysis indicated that Rst2p was a Cys(2)His(2) zinc-finger protein carrying 567 amino acid residues. Rst2p could bind specifically to a stress response element-like cis element located in the ste11 promoter region, which was important for ste11 expression. Meanwhile, transcription of ste11 was reduced significantly by a defective mutation in itself. An artificial supply of functional Ste11p circumvented this reduction. A complete Ste11p-binding motif (TR box) found in the promoter region was necessary for the full expression of ste11, suggesting that Ste11p is involved in the activation of ste11. We conclude that transcription of ste11 is under autoregulation in addition to control through the PKA-Rst2p pathway.


Asunto(s)
Proteínas Fúngicas/genética , Regulación Fúngica de la Expresión Génica , Regiones Promotoras Genéticas , Proteínas de Schizosaccharomyces pombe , Schizosaccharomyces/genética , Factores de Transcripción/genética , Factores de Transcripción/metabolismo , Transcripción Genética , Secuencia de Aminoácidos , Secuencia de Bases , Proteínas Quinasas Dependientes de Calcio-Calmodulina/metabolismo , Proteínas Fúngicas/metabolismo , Genes Fúngicos , Humanos , Datos de Secuencia Molecular , Sistemas de Lectura Abierta , Mapeo Restrictivo , Schizosaccharomyces/citología , Schizosaccharomyces/fisiología , Alineación de Secuencia , Homología de Secuencia de Aminoácido , Esporas Fúngicas , Factores de Transcripción/química , Dedos de Zinc
3.
Curr Genet ; 28(1): 32-8, 1995 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-8536311

RESUMEN

The Schizosaccharomyces pombe pac2 gene encodes a protein of 235 amino acids not similar to any protein of known function. Cells over-expressing pac2 were poor in mating and sporulation. Expression of ste11, which encodes a key transcription factor for sexual development, was not inducible by nitrogen starvation in these cells. Cells defective in pac2 could express ste11 and enter sexual development under incomplete starvation conditions. Although expression of ste11 is regulated primarily by the cAMP cascade, genetic analysis indicated that this cascade and pac2 can partially compensate for each other in the regulation of sexual development, and that neither of them is epistatic over the other. Thus, Pac2 appears to control ste11 expression via a signaling pathway independent of the cAMP cascade.


Asunto(s)
AMP Cíclico/metabolismo , Proteínas Fúngicas/fisiología , Proteínas de Schizosaccharomyces pombe , Schizosaccharomyces/fisiología , Secuencia de Aminoácidos , Secuencia de Bases , ADN Complementario , ADN de Hongos , Proteínas Fúngicas/genética , Datos de Secuencia Molecular , Fenotipo , Schizosaccharomyces/genética , Factores de Transcripción/genética
4.
J Biol Chem ; 269(13): 9632-7, 1994 Apr 01.
Artículo en Inglés | MEDLINE | ID: mdl-8144551

RESUMEN

We have isolated Schizosaccharomyces pombe genes that confer sterility to the fission yeast cell when expressed from a multicopy plasmid. One of these genes strongly hybridized to a probe carrying the open reading frame of Saccharomyces cerevisiae TPK1, which encodes a catalytic subunit of the cAMP-dependent protein kinase (protein kinase A). This S. pombe gene, named pka1, has a coding potential of 512 amino acids, and the deduced gene product is 60% identical with the S. cerevisiae Tpk1 protein in the C-terminal 320 amino acids. Disruption of pka1 slows cell growth but is not lethal. The resultant cells, however, are highly derepressed for sexual development, readily undergoing conjugation and sporulation in the absence of nitrogen starvation. They are, thus, phenotypically indistinguishable from the adenylyl cyclase-defective (cyr1-) cells previously characterized, except that the pka1- spores are retarded in germination, whereas the cyr1- spores are not. Disruption of pka1 is epistatic to a defect in cgs1, which encodes the regulatory subunit of protein kinase A. These results strongly suggest that the product of pka1 is a catalytic subunit of protein kinase A and, furthermore, that S. pombe has only one gene encoding it. This situation contrasts with the case of S. cerevisiae, in which three genes encode the catalytic subunits.


Asunto(s)
Proteínas Quinasas Dependientes de AMP Cíclico/genética , Genes Fúngicos , Schizosaccharomyces/enzimología , Schizosaccharomyces/genética , Secuencia de Aminoácidos , Animales , Secuencia de Bases , Southern Blotting , Secuencia Conservada , Proteínas Quinasas Dependientes de AMP Cíclico/biosíntesis , ADN de Hongos/análisis , Drosophila/enzimología , Drosophila/genética , Infertilidad , Sustancias Macromoleculares , Datos de Secuencia Molecular , Mutagénesis , Sistemas de Lectura Abierta , Plásmidos , Reacción en Cadena de la Polimerasa , Saccharomyces cerevisiae/genética , Schizosaccharomyces/fisiología , Homología de Secuencia de Aminoácido
5.
Phys Rev D Part Fields ; 48(8): 3793-3808, 1993 Oct 15.
Artículo en Inglés | MEDLINE | ID: mdl-10016654
6.
Phys Rev D Part Fields ; 35(4): 1318-1355, 1987 Feb 15.
Artículo en Inglés | MEDLINE | ID: mdl-9957792
7.
Phys Rev D Part Fields ; 35(4): 1356-1384, 1987 Feb 15.
Artículo en Inglés | MEDLINE | ID: mdl-9957793
8.
Phys Rev D Part Fields ; 34(8): 2360-2429, 1986 Oct 15.
Artículo en Inglés | MEDLINE | ID: mdl-9957428
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