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1.
Asian-Australas J Anim Sci ; 27(5): 628-34, 2014 May.
Artículo en Inglés | MEDLINE | ID: mdl-25049997

RESUMEN

Data on age and body weight at breeding, parity, previous litter size, days open and some descriptive body linear traits from 389 meat-type, prolific Black Bengal goats in Tripura State of India, were collected for 3 and 1/2 years (2007 to 2010) and analyzed using logistic regression model. The objectives of the study were i) to evaluate the effect of age and body weight at breeding, parity, previous litter size and days open on litter size of does; and ii) to investigate if body linear type traits influenced litter size in meat-type, prolific goats. The incidence of 68.39% multiple births with a prolificacy rate of 175.07% was recorded. Higher age (>2.69 year), higher parity order (>2.31), more body weight at breeding (>20.5 kg) and larger previous litter size (>1.65) showed an increase likelihood of multiple litter size when compared to single litter size. There was a strong, positive relationship between litter size and various body linear type traits like neck length (>22.78 cm), body length (>54.86 cm), withers height (>48.85 cm), croup height (>50.67 cm), distance between tuber coxae bones (>11.38 cm) and distance between tuber ischii bones (>4.56 cm) for discriminating the goats bearing multiple fetuses from those bearing a single fetus.

2.
J Cell Biol ; 174(7): 1047-58, 2006 Sep 25.
Artículo en Inglés | MEDLINE | ID: mdl-17000881

RESUMEN

Establishment of angiogenic circuits that orchestrate blood vessel development and remodeling requires an exquisite balance between the activities of pro- and antiangiogenic factors. However, the logic that permits complex signal integration by vascular endothelium is poorly understood. We demonstrate that a "neuropeptide," neurokinin-B (NK-B), reversibly inhibits endothelial cell vascular network assembly and opposes angiogenesis in the chicken chorioallantoic membrane. Disruption of endogenous NK-B signaling promoted angiogenesis. Mechanistic analyses defined a multicomponent pathway in which NK-B signaling converges upon cellular processes essential for angiogenesis. NK-B-mediated ablation of Ca2+ oscillations and elevation of 3'-5' [corrected] cyclic adenosine monophosphate (cAMP) reduced cellular proliferation, migration, and vascular endothelial growth factor receptor expression and induced the antiangiogenic protein calreticulin. Whereas NK-B initiated certain responses, other activities required additional stimuli that increase cAMP. Although NK-B is a neurotransmitter/ neuromodulator and NK-B overexpression characterizes the pregnancy-associated disorder preeclampsia, NK-B had not been linked to vascular remodeling. These results establish a conserved mechanism in which NK-B instigates multiple activities that collectively oppose vascular remodeling.


Asunto(s)
Inhibidores de la Angiogénesis/fisiología , Neuroquinina B/fisiología , Transducción de Señal/fisiología , Tromboxano A2/fisiología , 1-Metil-3-Isobutilxantina/farmacología , Inhibidores de la Angiogénesis/farmacología , Animales , Calcio/metabolismo , Señalización del Calcio/efectos de los fármacos , Línea Celular , Movimiento Celular/efectos de los fármacos , Embrión de Pollo , Membrana Corioalantoides/irrigación sanguínea , Membrana Corioalantoides/efectos de los fármacos , Regulación hacia Abajo/efectos de los fármacos , Sinergismo Farmacológico , Células Endoteliales/efectos de los fármacos , Células Endoteliales/fisiología , Ratones , Modelos Biológicos , Músculo Liso Vascular/fisiología , Neuroquinina B/farmacología , Neurotransmisores/farmacología , Neurotransmisores/fisiología , Receptores de Factores de Crecimiento Endotelial Vascular/fisiología , Transducción de Señal/efectos de los fármacos , Tromboxano A2/farmacología , Factor A de Crecimiento Endotelial Vascular/fisiología
3.
Mol Cell Biol ; 26(19): 7056-67, 2006 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-16980610

RESUMEN

The reciprocal expression of GATA-1 and GATA-2 during hematopoiesis is an important determinant of red blood cell development. Whereas Gata2 is preferentially transcribed early in hematopoiesis, elevated GATA-1 levels result in GATA-1 occupancy at sites upstream of the Gata2 locus and transcriptional repression. GATA-2 occupies these sites in the transcriptionally active locus, suggesting that a "GATA switch" abrogates GATA-2-mediated positive autoregulation. Chromatin immunoprecipitation (ChIP) coupled with genomic microarray analysis and quantitative ChIP analysis with GATA-1-null cells expressing an estrogen receptor ligand binding domain fusion to GATA-1 revealed additional GATA switches 77 kb upstream of Gata2 and within intron 4 at +9.5 kb. Despite indistinguishable GATA-1 occupancy at -77 kb and +9.5 kb versus other GATA switch sites, GATA-1 functioned uniquely at the different regions. GATA-1 induced histone deacetylation at and near Gata2 but not at the -77 kb region. The -77 kb region, which was DNase I hypersensitive in both active and inactive states, conferred equivalent enhancer activities in GATA-1- and GATA-2-expressing cells. By contrast, the +9.5 kb region exhibited considerably stronger enhancer activity in GATA-2- than in GATA-1-expressing cells, and other GATA switch sites were active only in GATA-1- or GATA-2-expressing cells. Chromosome conformation capture analysis demonstrated higher-order interactions between the -77 kb region and Gata2 in the active and repressed states. These results indicate that dispersed GATA factor complexes function via long-range chromatin interactions and qualitatively distinct activities to regulate Gata2 transcription.


Asunto(s)
Factor de Transcripción GATA1/genética , Factor de Transcripción GATA1/metabolismo , Factor de Transcripción GATA2/genética , Factor de Transcripción GATA2/metabolismo , Acetilación , Animales , Emparejamiento Base/genética , Secuencia de Bases , Cromatina/metabolismo , Inmunoprecipitación de Cromatina , Secuencia Conservada/genética , Desoxirribonucleasa I/metabolismo , Elementos de Facilitación Genéticos/genética , Humanos , Ratones , Datos de Secuencia Molecular , Proteínas Nucleares/metabolismo , Regiones Promotoras Genéticas/genética , Receptores de Estrógenos/metabolismo , Factores de Transcripción p300-CBP/metabolismo
4.
J Bacteriol ; 190(9): 3344-52, 2008 May.
Artículo en Inglés | MEDLINE | ID: mdl-18310328

RESUMEN

The peptidyl transferase center, present in domain V of 23S rRNA of eubacteria and large rRNA of plants and animals, can act as a general protein folding modulator. Here we show that a few specific nucleotides in Escherichia coli domain V RNA bind to unfolded proteins and, as shown previously, bring the trapped proteins to a folding-competent state before releasing them. These nucleotides are the same for the proteins studied so far: bovine carbonic anhydrase, lactate dehydrogenase, malate dehydrogenase, and chicken egg white lysozyme. The amino acids that interact with these nucleotides are also found to be specific in the two cases tested: bovine carbonic anhydrase and lysozyme. They are either neutral or positively charged and are present in random coils on the surface of the crystal structure of both the proteins. In fact, two of these amino acid-nucleotide pairs are identical in the two cases. How these features might help the process of protein folding is discussed.


Asunto(s)
Pliegue de Proteína , ARN Bacteriano/química , ARN Ribosómico 23S/química , Secuencia de Aminoácidos , Aminoácidos/química , Animales , Secuencia de Bases , Sitios de Unión , Bovinos , Embrión de Pollo , Cristalografía por Rayos X , Enzimas/química , Escherichia coli/genética , Escherichia coli/metabolismo , Datos de Secuencia Molecular , Conformación de Ácido Nucleico , Nucleótidos/química , Conformación Proteica , ARN Bacteriano/genética , ARN Ribosómico 23S/genética , Subunidades Ribosómicas Grandes Bacterianas/química , Espectrometría de Masa por Láser de Matriz Asistida de Ionización Desorción
5.
Nucleic Acids Res ; 30(5): 1278-85, 2002 Mar 01.
Artículo en Inglés | MEDLINE | ID: mdl-11861922

RESUMEN

The active site of a protein folding reaction is in domain V of the 23S rRNA in the bacterial ribosome and its homologs in other organisms. This domain has long been known as the peptidyl transferase center. Domain V of Bacillus subtilis is split into two segments, the more conserved large peptidyl transferase loop (RNA1) and the rest (RNA2). These two segments together act as a protein folding modulator as well as the complete domain V RNA. A number of site-directed mutations were introduced in RNA1 and RNA2 of B.subtilis, taking clues from reports of these sites being involved in various steps of protein synthesis. For example, sites like G2505, U2506, U2584 and U2585 in Escherichia coli RNA1 region are protected by deacylated tRNA at high Mg2+ concentration and A2602 is protected by amino acyl tRNA when the P site remains occupied already. Mutations A2058G and A2059G in the RNA1 region render the ribosome Ery(r )in E.coli and Lnc(r )in tobacco chloroplast. Sites in P loop G2252 and G2253 in E.coli are protected against modification by the CCA end of the P site bound tRNA. Mutations were introduced in corresponding nucleotides in B.subtilis RNA1 and RNA2 of domain V. The mutants were tested for refolding using unfolded protein binding assays with unfolded carbonic anhydrase. In the protein folding assay, the mutants showed partial to complete loss of this activity. In the filter binding assay for the RNA-refolding protein complex, the mutants showed an extent of protein binding that agreed well with their protein folding activity.


Asunto(s)
Bacillus subtilis/genética , ARN Ribosómico 23S/química , ARN Ribosómico 23S/metabolismo , Secuencia de Bases , Sitios de Unión , Anhidrasas Carbónicas/química , Anhidrasas Carbónicas/metabolismo , Cinética , Datos de Secuencia Molecular , Mutagénesis Sitio-Dirigida , Mutación , Conformación de Ácido Nucleico , Pliegue de Proteína , ARN Bacteriano/química , ARN Bacteriano/genética , ARN Bacteriano/metabolismo , ARN Ribosómico 23S/genética , Relación Estructura-Actividad
6.
Nucleic Acids Res ; 30(11): 2390-7, 2002 Jun 01.
Artículo en Inglés | MEDLINE | ID: mdl-12034826

RESUMEN

The role of the 50S particle of Escherichia coli ribosome and its 23S rRNA in the refolding and subunit association of dimeric porcine heart cytoplasmic malate dehydrogenase (s-MDH) has been investigated. The self-reconstitution of s-MDH is governed by two parallel pathways representing the folding of the inactive monomeric and the dimeric intermediates. However, in the presence of these folding modulators, only one first order kinetics was observed. To understand whether this involved the folding of the monomers or the dimers, subunit association of s-MDH was studied using fluorescein-5-isothiocyanate-rhodamine-isothiocyanate (FITC-RITC) fluorescence energy transfer and chemical cross-linking with gluteraldehyde. The observation suggests that during refolding the interaction of the unstructured monomers of s-MDH with these ribosomal folding modulators leads to very fast formation of structured monomers that immediately dimerise. These inactive dimers then fold to the native ones, which is the rate limiting step in 23S or 50S assisted refolding of s-MDH. Furthermore, the sequential action of the two fragments of domain V of 23S rRNA has been investigated in order to elucidate the mechanism. The central loop of domain V of 23S rRNA (RNA1) traps the monomeric intermediates, and when they are released by the upper stem-loop region of the domain V of 23S rRNA (RNA2) they are already structured enough to form dimeric intermediates which are directed towards the proper folding pathway.


Asunto(s)
Malato Deshidrogenasa/química , Malato Deshidrogenasa/metabolismo , Miocardio/enzimología , Pliegue de Proteína , ARN Bacteriano/metabolismo , ARN Ribosómico 23S/metabolismo , Animales , Bacillus subtilis/genética , Secuencia de Bases , Cromatografía en Gel , Reactivos de Enlaces Cruzados/metabolismo , Dimerización , Transferencia de Energía , Escherichia coli/genética , Fluorescencia , Glutaral/metabolismo , Cinética , Chaperonas Moleculares/química , Chaperonas Moleculares/genética , Chaperonas Moleculares/metabolismo , Peso Molecular , Conformación de Ácido Nucleico , Desnaturalización Proteica , Renaturación de Proteína , Estructura Cuaternaria de Proteína , Subunidades de Proteína , ARN Bacteriano/química , ARN Bacteriano/genética , ARN Ribosómico 23S/química , ARN Ribosómico 23S/genética , Porcinos
7.
J Parasit Dis ; 40(3): 914-8, 2016 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-27605809

RESUMEN

Six cases of coenurosis were reported in a local Black Bengal goat within the age group of 6 months to 1 and half years with the complaint of swelling present on the body surfaces at different anatomical sites. On palpation, the swelling was non-painful and fluctuating uniformly under the skin. All the animals exhibited almost similar signs and symptoms except for three animals which had mild gastro-intestinal problems. All the clinical parameters (heart rate, respiratory rate and rectal temperature) and blood haemoglobin levels (range 10-12 g %) were within the normal physiological limits. After sedation and restraint with Sequil (Triflupromazine HCl 1 mg/kg, IM), the cysts were removed carefully to avoid breakage. Identification was done on the basis of morphology and microscopic studies of scolices, suckers, pattern of rostellum and hooks present which gives confirmation of the cysts under discussion as Taenia gaigeri. All the animals recovered uneventfully from surgery after one week without any complications and on record there was no reoccurrence of the condition within 1 and half months of observation.

8.
Anim Reprod Sci ; 140(1-2): 54-61, 2013 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-23787106

RESUMEN

Identifying prolificacy potential and determination of fetal number during pregnancy for proper care and management of the pregnant goats bearing multiple fetuses and achieving the benefits out of multiple births are essential for sustainable goat farming. Our objectives were (1) to examine prolificacy potential in goats by using pituitary response to gonadotrophin releasing hormone (GnRH) challenge test, (2) to investigate hormonal profiles for the prediction of fetal number in pregnant goats and (3) to find out the most reliable timing of blood sampling for discriminating prolificacy trait and differentiating the goats bearing single, twin and triplet fetuses. In first experiment (GnRH challenge test), plasma FSH concentrations were significantly higher (P<0.01) among the goats belonging to triplet vs. twin vs. single kidding size groups after GnRH administration. Multivariate stepwise discriminant function analysis recognized that one blood sampling at 220min after GnRH administration can be used to distinguish prolificacy potential in goats. In second experiment, plasma progesterone levels were significantly higher (P<0.01) in goats bearing triplet vs. twin vs. single fetus between day 84 and 21 prior to parturition. Plasma estrone sulphate concentrations were found to be higher (P<0.05) in does bearing multiple fetuses than the does bearing single fetus between day 126 and 28 prior to parturition. A single blood sampling at day 63 prior to parturition was the most probable suitable time for discriminating kidding size by using plasma progesterone as marker.


Asunto(s)
Cabras/fisiología , Hormona Liberadora de Gonadotropina/farmacología , Embarazo Múltiple/fisiología , Animales , Análisis Discriminante , Estrona/análogos & derivados , Estrona/sangre , Femenino , Feto , Hormona Folículo Estimulante/sangre , Cabras/sangre , Hormona Luteinizante/sangre , Masculino , Embarazo , Embarazo Múltiple/sangre , Progesterona/sangre
9.
J Ethnopharmacol ; 134(1): 62-6, 2011 Mar 08.
Artículo en Inglés | MEDLINE | ID: mdl-21130149

RESUMEN

ETHNOPHARMACOLOGICAL RELEVANCE: Leaves of Plantago erosa ex Roxb are used traditionally in Northeast India in different illnesses which include wounds, cuts, bruises, insect bites, poison-ivy rashes, minor sores and snakebite, etc. AIM OF THE STUDY: Plantago erosa is one of the commonly used medicinal plants in various inflammatory conditions in this region; however, due to paucity of scientific literature on its anti-inflammatory property, the present study was aimed at evaluating its anti-inflammatory activity in the leaves using in vivo models of inflammation. MATERIALS AND METHODS: Different models like carageenan induced paw edema in rat and mice, formalin induced paw licking in rats and cotton pellet induced granuloma in rats were used for studying the anti-inflammatory activity in methanol extract of Plantago erosa (PEME) leaves. RESULTS: The PEME at the oral doses from 300 to 600 mg/kg showed anti-inflammatory activity in various models. The extract (PEME) reduced carageenan induced paw edema in rat and mice, inhibited the formation of granulomatous tissue in cotton pellet induced granuloma after treatment and also decreased the reaction time in both early and late phases in formalin induced paw licking in rats. CONCLUSION: The study evidently confirmed anti-inflammatory activity of PEME and thus supported the traditional claim. The anti-inflammatory activity could be attributed to the phytoconstituent (flavonoids, alkaloids and steroid) present in the methanol extract of the plant.


Asunto(s)
Antiinflamatorios/farmacología , Hojas de la Planta/química , Plantago/química , Animales , Masculino , Ratones , Ratas , Ratas Wistar
10.
J Cell Physiol ; 205(1): 1-9, 2005 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-15887235

RESUMEN

Despite the extraordinary task of packaging mammalian DNA within the constraints of a cell nucleus, individual genes assemble into cell type-specific chromatin structures with high fidelity. This chromatin architecture is a crucial determinant of gene expression signatures that distinguish specific cell types. Whereas extensive progress has been made on defining biochemical and molecular mechanisms of chromatin modification and remodeling, many questions remain unanswered about how cell type-specific chromatin domains assemble and are regulated. This mini-review will discuss emerging studies on how interplay among members of the GATA family of transcription factors establishes and regulates chromatin domains. Dissecting mechanisms underlying the function of hematopoietic GATA factors has revealed fundamental insights into the control of blood cell development from hematopoietic stem cells and the etiology of pathological states in which hematopoiesis is perturbed.


Asunto(s)
Diferenciación Celular , Cromatina/genética , Cromatina/metabolismo , Proteínas de Unión al ADN/metabolismo , Factores de Transcripción/metabolismo , Animales , Cromatina/química , Proteínas de Unión al ADN/química , Proteínas de Unión al ADN/genética , Factores de Unión al ADN Específico de las Células Eritroides , Hematopoyesis , Humanos , Modelos Biológicos , Factores de Transcripción/química , Factores de Transcripción/genética
11.
Proc Natl Acad Sci U S A ; 100(15): 8811-6, 2003 Jul 22.
Artículo en Inglés | MEDLINE | ID: mdl-12857954

RESUMEN

Interplay among GATA transcription factors is an important determinant of cell fate during hematopoiesis. Although GATA-2 regulates hematopoietic stem cell function, mechanisms controlling GATA-2 expression are undefined. Of particular interest is the repression of GATA-2, because sustained GATA-2 expression in hematopoietic stem and progenitor cells alters hematopoiesis. GATA-2 transcription is derepressed in erythroid precursors lacking GATA-1, but the underlying mechanisms are unknown. Using chromatin immunoprecipitation analysis, we show that GATA-1 binds a highly restricted upstream region of the approximately 70-kb GATA-2 domain, despite >80 GATA sites throughout the domain. GATA-2 also binds this region in the absence of GATA-1. Genetic complementation studies in GATA-1-null cells showed that GATA-1 rapidly displaces GATA-2, which is coupled to transcriptional repression. GATA-1 also displaces CREB-binding protein (CBP), despite the fact that GATA-1 binds CBP in other contexts. Repression correlates with reduced histone acetylation domain-wide, but not altered methylation of histone H3 at lysine 4. The GATA factor-binding region exhibited cell-type-specific enhancer activity in transient transfection assays. We propose that GATA-1 instigates GATA-2 repression by means of disruption of positive autoregulation, followed by establishment of a domain-wide repressive chromatin structure. Such a mechanism is predicted to be critical for the control of hematopoiesis.


Asunto(s)
Cromatina/metabolismo , Proteínas de Unión al ADN/metabolismo , Proteínas Represoras/metabolismo , Factores de Transcripción/metabolismo , Animales , Secuencia de Bases , Sitios de Unión/genética , Línea Celular , Cromatina/química , ADN/genética , Proteínas de Unión al ADN/química , Proteínas de Unión al ADN/genética , Factores de Unión al ADN Específico de las Células Eritroides , Factor de Transcripción GATA1 , Factor de Transcripción GATA2 , Hematopoyesis , Histonas/química , Histonas/metabolismo , Homeostasis , Humanos , Ratones , Modelos Biológicos , Datos de Secuencia Molecular , Estructura Terciaria de Proteína , Proteínas Represoras/química , Proteínas Represoras/genética , Factores de Transcripción/química , Factores de Transcripción/genética , Transcripción Genética
12.
Mol Microbiol ; 48(6): 1679-92, 2003 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-12791147

RESUMEN

Bacterial ribosomes or their 50S subunit can refold many unfolded proteins. The folding activity resides in domain V of 23S RNA of the 50S subunit. Here we show that ribosomes can also refold a denatured chaperone, DnaK, in vitro, and the activity may apply in the folding of nascent DnaK polypeptides in vivo. The chaperone was unusual as the native protein associated with the 50S subunit stably with a 1:1 stoichiometry in vitro. The binding site of the native protein appears to be different from the domain V of 23S RNA, the region with which denatured proteins interact. The DnaK binding influenced the protein folding activity of domain V modestly. Conversely, denatured protein binding to domain V led to dissociation of the native chaperone from the 50S subunit. DnaK thus appears to depend on ribosomes for its own folding, and upon folding, can rebind to ribosome to modulate its general protein folding activity.


Asunto(s)
Proteínas de Escherichia coli , Proteínas HSP70 de Choque Térmico/metabolismo , Pliegue de Proteína , Ribosomas/metabolismo , Animales , Anhidrasas Carbónicas/metabolismo , Bovinos , Escherichia coli/genética , Escherichia coli/metabolismo , Proteínas HSP70 de Choque Térmico/química , Proteínas HSP70 de Choque Térmico/genética , Conformación Proteica , ARN Ribosómico 23S/genética , ARN Ribosómico 23S/metabolismo , Proteínas Ribosómicas/metabolismo
13.
J Biol Chem ; 279(30): 31348-56, 2004 Jul 23.
Artículo en Inglés | MEDLINE | ID: mdl-15123623

RESUMEN

The GATA family of transcription factors establishes genetic networks that control developmental processes including hematopoiesis, vasculogenesis, and cardiogenesis. We found that GATA-1 strongly activates transcription of the Tac-2 gene, which encodes proneurokinin-B, a precursor of neurokinin-B (NK-B). Neurokinins function through G protein-coupled transmembrane receptors to mediate diverse physiological responses including pain perception and the control of vascular tone. Whereas an elevated level of NK-B was implicated in pregnancy-associated pre-eclampsia (Page, N. M., Woods, R. J., Gardiner, S. M., Lomthaisong, K., Gladwell, R. T., Butlin, D. J., Manyonda, I. T., and Lowry, P. J. (2000) Nature 405, 797-800), the regulation of NK-B synthesis and function are poorly understood. Tac-2 was expressed in normal murine erythroid cells and was induced upon ex vivo erythropoiesis. An estrogen receptor fusion to GATA-1 (ER-GATA-1) and endogenous GATA-1 both occupied a region of Tac-2 intron-7, which contains two conserved GATA motifs. Genetic complementation analysis in GATA-1-null G1E cells revealed that endogenous GATA-2 occupied the same region of intron-7, and expression of ER-GATA-1 displaced GATA-2 and activated Tac-2 transcription. Erythroid cells did not express neurokinin receptors, whereas aortic and yolk sac endothelial cells differentially expressed neurokinin receptor subtypes. Since NK-B induced cAMP accumulation in yolk sac endothelial cells, these results suggest a new mode of vascular regulation in which GATA-1 controls NK-B synthesis in erythroid cells.


Asunto(s)
Proteínas de Unión al ADN/genética , Proteínas de Unión al ADN/metabolismo , Células Eritroides/metabolismo , Neuroquinina B/genética , Factores de Transcripción/genética , Factores de Transcripción/metabolismo , Animales , Secuencia de Bases , Línea Celular , Cartilla de ADN/genética , Factores de Unión al ADN Específico de las Células Eritroides , Femenino , Factor de Transcripción GATA1 , Humanos , Técnicas In Vitro , Ratones , Ratones Endogámicos C57BL , Modelos Biológicos , Análisis de Secuencia por Matrices de Oligonucleótidos , Precursores de Proteínas/genética , ARN Mensajero/genética , ARN Mensajero/metabolismo , Taquicininas/genética , Activación Transcripcional
14.
Proc Natl Acad Sci U S A ; 101(4): 980-5, 2004 Jan 27.
Artículo en Inglés | MEDLINE | ID: mdl-14715908

RESUMEN

Coregulator recruitment by DNA-bound factors results in chromatin modification and protein-protein interactions, which regulate transcription. However, the mechanism by which the Friend of GATA (FOG) coregulator mediates GATA factor-dependent transcription is unknown. We showed previously that GATA-1 replaces GATA-2 at an upstream region of the GATA-2 locus, and that this GATA switch represses GATA-2. Genetic complementation analysis in FOG-1-null hematopoietic precursors revealed that FOG-1 is not required for establishment or maintenance of the active GATA-2 domain, but is critical for the GATA switch. Analysis of GATA factor binding to additional loci also revealed FOG-1-dependent GATA switches. Thus, FOG-1 facilitates chromatin occupancy by GATA-1 at sites bound by GATA-2. We propose that FOG-1 is a prototype of a new class of coregulators termed chromatin occupancy facilitators, which confer coregulation in certain contexts via enhancing trans-acting factor binding to chromatin in vivo.


Asunto(s)
Cromatina/metabolismo , Proteínas de Unión al ADN/fisiología , Factores de Transcripción/fisiología , Proteínas Portadoras/fisiología , Línea Celular Transformada , Proteínas de Unión al ADN/genética , Factores de Unión al ADN Específico de las Células Eritroides , Factor de Transcripción GATA2 , Proteínas Nucleares/fisiología , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Factores de Transcripción/genética , Transcripción Genética
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