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1.
Leukemia ; 32(3): 616-625, 2018 03.
Artículo en Inglés | MEDLINE | ID: mdl-28904384

RESUMEN

Although substantial progress has been made in the treatment of B-cell acute lymphoblastic leukemia (B-ALL), the prognosis of patients with either refractory or relapsed B-ALL remains dismal. Novel therapeutic strategies are needed to improve the outcome of these patients. KPT-9274 is a novel dual inhibitor of p21-activated kinase 4 (PAK4) and nicotinamide phosphoribosyltransferase (NAMPT). PAK4 is a serine/threonine kinase that regulates a variety of fundamental cellular processes. NAMPT is a rate-limiting enzyme in the salvage biosynthesis pathway of nicotinamide adenine dinucleotide (NAD) that plays a vital role in energy metabolism. Here, we show that KPT-9274 strongly inhibits B-ALL cell growth regardless of cytogenetic abnormalities. We also demonstrate the potent in vivo efficacy and tolerability of KPT-9274 in a patient-derived xenograft murine model of B-ALL. Interestingly, although KPT-9274 is a dual PAK4/NAMPT inhibitor, B-ALL cell growth inhibition by KPT-9274 was largely abolished with nicotinic acid supplementation, indicating that the inhibitory effects on B-ALL cells are mainly exerted by NAD+ depletion through NAMPT inhibition. Moreover, we have found that the extreme susceptibility of B-ALL cells to NAMPT inhibition is related to the reduced cellular NAD+ reserve. NAD+ depletion may be a promising alternative approach to treating patients with B-ALL.


Asunto(s)
NAD/metabolismo , Leucemia-Linfoma Linfoblástico de Células Precursoras B/metabolismo , Acrilamidas/química , Acrilamidas/farmacología , Aminopiridinas/química , Aminopiridinas/farmacología , Animales , Antineoplásicos/química , Antineoplásicos/farmacología , Apoptosis/efectos de los fármacos , Línea Celular Tumoral , Proliferación Celular/efectos de los fármacos , Supervivencia Celular/efectos de los fármacos , Citocinas/antagonistas & inhibidores , Modelos Animales de Enfermedad , Femenino , Humanos , Masculino , Ratones , Nicotinamida Fosforribosiltransferasa/antagonistas & inhibidores , Leucemia-Linfoma Linfoblástico de Células Precursoras B/tratamiento farmacológico , Leucemia-Linfoma Linfoblástico de Células Precursoras B/patología , Transducción de Señal/efectos de los fármacos , Ensayos Antitumor por Modelo de Xenoinjerto , Quinasas p21 Activadas/antagonistas & inhibidores
2.
Oncogenesis ; 6(2): e297, 2017 Feb 13.
Artículo en Inglés | MEDLINE | ID: mdl-28194033

RESUMEN

Long non-coding RNAs (lncRNAs) have a critical role in cancer initiation and progression, and thus may mediate oncogenic or tumor suppressing effects, as well as be a new class of cancer therapeutic targets. We performed high-throughput sequencing of RNA (RNA-seq) to investigate the expression level of lncRNAs and protein-coding genes in 30 esophageal samples, comprised of 15 esophageal squamous cell carcinoma (ESCC) samples and their 15 paired non-tumor tissues. We further developed an integrative bioinformatics method, denoted URW-LPE, to identify key functional lncRNAs that regulate expression of downstream protein-coding genes in ESCC. A number of known onco-lncRNA and many putative novel ones were effectively identified by URW-LPE. Importantly, we identified lncRNA625 as a novel regulator of ESCC cell proliferation, invasion and migration. ESCC patients with high lncRNA625 expression had significantly shorter survival time than those with low expression. LncRNA625 also showed specific prognostic value for patients with metastatic ESCC. Finally, we identified E1A-binding protein p300 (EP300) as a downstream executor of lncRNA625-induced transcriptional responses. These findings establish a catalog of novel cancer-associated functional lncRNAs, which will promote our understanding of lncRNA-mediated regulation in this malignancy.

3.
Leukemia ; 31(1): 1-10, 2017 01.
Artículo en Inglés | MEDLINE | ID: mdl-27389053

RESUMEN

Partial tandem duplication of MLL (MLL-PTD) characterizes acute myeloid leukemia (AML) patients often with a poor prognosis. To understand the order of occurrence of MLL-PTD in relation to other major AML mutations and to identify novel mutations that may be present in this unique AML molecular subtype, exome and targeted sequencing was performed on 85 MLL-PTD AML samples using HiSeq-2000. Genes involved in the cohesin complex (STAG2), a splicing factor (U2AF1) and a poorly studied gene, MGA were recurrently mutated, whereas NPM1, one of the most frequently mutated AML gene, was not mutated in MLL-PTD patients. Interestingly, clonality analysis suggests that IDH2/1, DNMT3A, U2AF1 and TET2 mutations are clonal and occur early, and MLL-PTD likely arises after these initial mutations. Conversely, proliferative mutations (FLT3, RAS), typically appear later, are largely subclonal and tend to be unstable. This study provides important insights for understanding the relative importance of different mutations for defining a targeted therapeutic strategy for MLL-PTD AML patients.


Asunto(s)
N-Metiltransferasa de Histona-Lisina/genética , Leucemia Mieloide Aguda/genética , Mutación , Proteína de la Leucemia Mieloide-Linfoide/genética , Proliferación Celular/genética , Células Clonales , Exoma , Humanos , Tasa de Mutación , Nucleofosmina , Secuencias Repetidas en Tándem , Factores de Tiempo
5.
Oncogene ; 36(16): 2243-2254, 2017 04 20.
Artículo en Inglés | MEDLINE | ID: mdl-27819679

RESUMEN

ZNF750 controls epithelial homeostasis by regulating epidermal-differentiation genes, a role underscored by its pathogenic mutations in esophageal squamous cell cancers (SCCs). However, the precise role of ZNF750 in SCC cell biology remains unclear. In this study, we report that ZNF750 is exclusively deleted, mutated and underexpressed in human SCCs, and low ZNF750 expression is associated with poor survival. Restoration of wildtype, but not mutant ZNF750 protein uniquely inhibited the malignant phenotypes of SCC cells both in vitro and in vivo. Notably, ZNF750 promoted the expression of a long non-coding RNA (TINCR), which mediated both cancer-inhibition and differentiation-induction effects of ZNF750. In addition, ZNF750 potently suppressed cell migration by directly inhibiting the transactivation of LAMC2. Together, our findings characterize ZNF750 as a crucial SCC-specific suppressor and uncover its novel anticancer-associated functions.


Asunto(s)
Carcinoma de Células Escamosas/genética , Neoplasias Esofágicas/genética , Genes Supresores de Tumor , Factores de Transcripción/genética , Animales , Carcinoma de Células Escamosas/fisiopatología , Diferenciación Celular/genética , Línea Celular Tumoral , Linaje de la Célula , Movimiento Celular , ADN de Neoplasias , Neoplasias Esofágicas/fisiopatología , Femenino , Eliminación de Gen , Regulación Neoplásica de la Expresión Génica , Células HEK293 , Neoplasias de Cabeza y Cuello/genética , Humanos , Laminina/genética , Ratones , Ratones Endogámicos NOD , Mutación , Análisis de Secuencia por Matrices de Oligonucleótidos , Pronóstico , ARN Largo no Codificante , Factores de Transcripción/metabolismo , Transcriptoma , Proteínas Supresoras de Tumor/metabolismo , Neoplasias del Cuello Uterino/genética , Neoplasias del Cuello Uterino/fisiopatología
6.
Leukemia ; 30(5): 1155-65, 2016 05.
Artículo en Inglés | MEDLINE | ID: mdl-26847029

RESUMEN

BCOR is a component of a variant Polycomb group repressive complex 1 (PRC1). Recently, we and others reported recurrent somatic BCOR loss-of-function mutations in myelodysplastic syndrome and acute myelogenous leukemia (AML). However, the role of BCOR in normal hematopoiesis is largely unknown. Here, we explored the function of BCOR in myeloid cells using myeloid murine models with Bcor conditional loss-of-function or overexpression alleles. Bcor mutant bone marrow cells showed significantly higher proliferation and differentiation rates with upregulated expression of Hox genes. Mutation of Bcor reduced protein levels of RING1B, an H2A ubiquitin ligase subunit of PRC1 family complexes and reduced H2AK119ub upstream of upregulated HoxA genes. Global RNA expression profiling in murine cells and AML patient samples with BCOR loss-of-function mutation suggested that loss of BCOR expression is associated with enhanced cell proliferation and myeloid differentiation. Our results strongly suggest that BCOR plays an indispensable role in hematopoiesis by inhibiting myeloid cell proliferation and differentiation and offer a mechanistic explanation for how BCOR regulates gene expression such as Hox genes.


Asunto(s)
Diferenciación Celular , Proliferación Celular , Células Progenitoras Mieloides/citología , Proteínas Represoras/fisiología , Animales , Regulación de la Expresión Génica , Genes Homeobox/genética , Hematopoyesis , Humanos , Leucemia Mieloide Aguda/patología , Ratones , Mutagénesis Sitio-Dirigida , Complejo Represivo Polycomb 1/fisiología , Proteínas Represoras/genética
7.
Oncogene ; 34(11): 1463-74, 2015 Mar 12.
Artículo en Inglés | MEDLINE | ID: mdl-24704825

RESUMEN

LNK (SH2B3) is an adaptor protein studied extensively in normal and malignant hematopoietic cells. In these cells, it downregulates activated tyrosine kinases at the cell surface resulting in an antiproliferative effect. To date, no studies have examined activities of LNK in solid tumors. In this study, we found by in silico analysis and staining tissue arrays that the levels of LNK expression were elevated in high-grade ovarian cancer. To test the functional importance of this observation, LNK was either overexpressed or silenced in several ovarian cancer cell lines. Remarkably, overexpression of LNK rendered the cells resistant to death induced by either serum starvation or nutrient deprivation, and generated larger tumors using a murine xenograft model. In contrast, silencing of LNK decreased ovarian cancer cell growth in vitro and in vivo. Western blot studies indicated that overexpression of LNK upregulated and extended the transduction of the mitogenic signal, whereas silencing of LNK produced the opposite effects. Furthermore, forced expression of LNK reduced cell size, inhibited cell migration and markedly enhanced cell adhesion. Liquid chromatography-mass spectroscopy identified 14-3-3 as one of the LNK-binding partners. Our results suggest that in contrast to the findings in hematologic malignancies, the adaptor protein LNK acts as a positive signal transduction modulator in ovarian cancers.


Asunto(s)
Proteínas 14-3-3/metabolismo , Proliferación Celular/fisiología , Neoplasias Ováricas/patología , Proteínas/metabolismo , Proteínas Adaptadoras Transductoras de Señales , Animales , Adhesión Celular/fisiología , Línea Celular Tumoral , Movimiento Celular/fisiología , Tamaño de la Célula , Femenino , Humanos , Péptidos y Proteínas de Señalización Intracelular , Ratones , Ratones Endogámicos NOD , Ratones SCID , Proteínas Quinasas Activadas por Mitógenos/metabolismo , Trasplante de Neoplasias , Unión Proteica , Proteínas/genética , Proteínas Proto-Oncogénicas c-akt/metabolismo , Transducción de Señal , Trasplante Heterólogo
8.
Dis Esophagus ; 28(1): 1-10, 2015 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-23826861

RESUMEN

Over the past two decades, there has been an increase in the number of anti-reflux operations being performed. This is mostly due to the use of laparoscopic techniques, the increasing prevalence of gastroesophageal reflux disease (GERD) in the population, and the increasing unwillingness of patients to take acid suppressive medications for life. Laparoscopic fundoplication is now widely available in both academic and community hospitals, has a limited length of stay and postoperative recovery time, and is associated with excellent outcomes in carefully selected patients. Although the operation has low mortality and postoperative morbidity, it is associated with late postoperative complications, such as gas bloat syndrome, dysphagia, diarrhea, and recurrent GERD symptoms. This review summarizes the diagnostic evaluation and appropriate management of such postoperative complications. If a reoperation is needed, it should be performed by experienced foregut surgeons.


Asunto(s)
Fundoplicación/efectos adversos , Reflujo Gastroesofágico/cirugía , Complicaciones Posoperatorias/terapia , Trastornos de Deglución/etiología , Trastornos de Deglución/terapia , Diarrea/etiología , Diarrea/terapia , Humanos , Laparoscopía/métodos , Complicaciones Posoperatorias/etiología , Recurrencia , Reoperación
9.
Oncogene ; 33(18): 2375-84, 2014 May 01.
Artículo en Inglés | MEDLINE | ID: mdl-23708664

RESUMEN

Breast cancer is the most common solid tumor and the second most common cause of death in women. Despite a large body of literature and progress in breast cancer research, many molecular aspects of this complex disease are still poorly understood, hindering the design of specific and effective therapeutic strategies. To identify the molecules important in breast cancer progression and metastasis, we tested the in vivo effects of inhibiting the functions of various kinases and genes involved in the regulation/modulation of the cytoskeleton by downregulating them in mouse PyMT mammary tumor cells and human breast cancer cell lines. These kinases and cytoskeletal regulators were selected based on their prognostic values for breast cancer patient survival. PyMT tumor cells, in which a selected gene was stably knocked down were injected into the tail veins of mice, and the formation of tumors in the lungs was monitored. One of the several genes found to be important for tumor growth in the lungs was NIMA-related kinases 2 (Nek2), a cell cycle-related protein kinase. Furthermore, Nek2 was also important for tumor growth in the mammary fat pad. In various human breast cancer cell lines, Nek2 knockdown induced aneuploidy and cell cycle arrest that led to cell death. Significantly, the breast cancer cell line most sensitive to Nek2 depletion was of the triple negative breast cancer subtype. Our data indicate that Nek2 has a pivotal role in breast cancer growth at primary and secondary sites, and thus may be an attractive and novel therapeutic target for this disease.


Asunto(s)
Aneuploidia , Neoplasias de la Mama/genética , Neoplasias de la Mama/patología , Centrosoma/patología , Proteínas Serina-Treonina Quinasas/fisiología , Animales , Línea Celular Tumoral , Segregación Cromosómica/genética , Femenino , Técnicas de Silenciamiento del Gen , Humanos , Neoplasias Pulmonares/secundario , Ratones , Quinasas Relacionadas con NIMA , Trasplante de Neoplasias , Proteínas Serina-Treonina Quinasas/genética
10.
Allergy ; 67(7): 920-8, 2012 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-22676062

RESUMEN

BACKGROUND: Chronic rhinosinusitis (CRS) is a disease characterized by inflammation of the nasal mucosa and paranasal sinuses. This inflammation may result in part from decreased epithelial barrier and innate immune responses, leading to frequent bacterial and fungal colonization. The objectives of this study were to investigate the expression of innate immune proteins of the palate lung and nasal epithelium clone (PLUNC) family in patients with CRS. METHODS: Nasal tissue samples were collected from control subjects and CRS patients with and without nasal polyps. Expression of the members of the PLUNC family was analyzed by real-time PCR. Expression of SPLUNC1 and LPLUNC2 proteins was analyzed by ELISA, immunoblot, and immunohistochemical analysis. RESULTS: Levels of mRNA for most of the members of the PLUNC family were profoundly reduced in nasal polyps (NPs) compared to uncinate tissue from control subjects or patients with CRS. LPLUNC2 and SPLUNC1 proteins were decreased in NPs of patients with CRS compared to uncinate tissue from control subjects. Immunohistochemical data revealed that within submucosal glands of sinonasal tissues, SPLUNC1 and LPLUNC2 were differentially expressed, in serous and mucous cells, respectively. The decrease in the expression of these molecules is probably explained by a decrease in the number of glands in NPs as revealed by correlations with levels of the glandular marker lactoferrin. CONCLUSIONS: Decreased SPLUNC1 and LPLUNC2 in NPs reflect a profound decrease in the number of submucosal glands. Decreased glands may lead to a localized defect in the production and release of glandular innate defense molecules.


Asunto(s)
Expresión Génica , Glicoproteínas/genética , Pólipos Nasales/genética , Fosfoproteínas/genética , Rinitis/genética , Sinusitis/genética , Adolescente , Adulto , Anciano , Enfermedad Crónica , Femenino , Perfilación de la Expresión Génica , Regulación de la Expresión Génica , Glicoproteínas/inmunología , Humanos , Lactoferrina/genética , Lactoferrina/inmunología , Masculino , Persona de Mediana Edad , Mucosa Nasal/inmunología , Mucosa Nasal/metabolismo , Pólipos Nasales/inmunología , Fosfoproteínas/inmunología , Rinitis/inmunología , Sinusitis/inmunología , Adulto Joven
11.
Oncogene ; 28(42): 3714-22, 2009 Oct 22.
Artículo en Inglés | MEDLINE | ID: mdl-19684620

RESUMEN

We have shown earlier that overexpression of Calreticulin (CRT) contributed to a poor prognosis for patients with esophageal squamous cell carcinoma (ESCC). Here, we have shown an important role of CRT in tumorigenesis through enhancing cell motility and anoikis resistance. SiRNA-mediated knockdown of CRT caused impaired cell migration, invasion and resistance to anoikis. Notably, CRT downregulation decreased the expression of Cortactin (CTTN), which has been previously reported as a candidate oncogene associated with anoikis through the PI3K-Akt pathway. In addition, Akt phosphorylation was abolished after CRT downregulation and its activation can be refreshed by CRT upregulation, suggesting that CRT-enhanced cell resistance to anoikis through the CRT-CTTN-PI3K-Akt pathway. Moreover, the CTTN mRNA level was decreased in CRT-siRNA cells, coupled with the inactivation of STAT3. Expression of both CTTN and p-STAT3 was reduced in tumor cells following incubation with the JAK-specific inhibitor, AG490. Chromatin immunoprecipitation assay showed direct binding of p-STAT3 to the conservative STAT3-binding sequences in CTTN promoter. Furthermore, overexpression of CTTN in CRT-downregulated ESCC cells restored its motility and resistance to anoikis. This study not only reveals a role of CRT in motility promotion and anoikis resistance in ESCC cells, but also identifies CRT as an upstream regulator in the CRT-STAT3-CTTN-Akt pathway.


Asunto(s)
Anoicis , Calreticulina/metabolismo , Carcinoma de Células Escamosas/patología , Movimiento Celular , Cortactina/metabolismo , Neoplasias Esofágicas/patología , Proteínas Proto-Oncogénicas c-akt/metabolismo , Factor de Transcripción STAT3/metabolismo , Agar , Animales , Calreticulina/deficiencia , Calreticulina/genética , Carcinoma de Células Escamosas/genética , Línea Celular Tumoral , Cortactina/genética , Regulación hacia Abajo , Neoplasias Esofágicas/genética , Femenino , Regulación Neoplásica de la Expresión Génica , Humanos , Ratones , Ratones Desnudos , Regiones Promotoras Genéticas/genética , Interferencia de ARN , Transducción de Señal , Transcripción Genética
12.
Dis Esophagus ; 22(1): 9-20, 2009.
Artículo en Inglés | MEDLINE | ID: mdl-18564170

RESUMEN

Esophageal squamous cell carcinoma (ESCC) is the predominant histological subtype of esophageal cancer in Asia, characterized by high incidence and mortality rate. Although significant progress has been made in surgery and adjuvant chemoradiotherapy, the prognosis of the patients with this cancer still remains poor. Investigation into protein alterations that occurred in tumors can provide clues to discover new biomarkers for improving diagnosis and guiding targeted therapy. Hundreds of papers have appeared over the past several decades concerning protein alterations in ESCC. This review summarizes all the dysregulated proteins investigated in the disease from 187 published papers and analyzes their contributions to tumor development and progression. We document protein alterations associated with tumor metastasis and the transition from normal esophageal epithelia to dysplasia in order to reveal the most useful markers for prediction of clinical outcome, early detection, and identification of high-risk patients for targeted therapies. In particular, we discuss the largest and most rigorous studies on prognostic implications of proteins in ESCC, in which cyclin D1, p53, E-cadherin and VEGF appeared to have the strongest evidence as independent predictors of patient outcome.


Asunto(s)
Carcinoma de Células Escamosas/genética , Neoplasias Esofágicas/genética , Proteínas de Neoplasias/genética , Apoptosis/genética , Apoptosis/fisiología , Biomarcadores de Tumor/metabolismo , Carcinoma de Células Escamosas/metabolismo , Carcinoma de Células Escamosas/patología , Proteínas de Ciclo Celular/genética , Ciclina D1/metabolismo , Progresión de la Enfermedad , Neoplasias Esofágicas/metabolismo , Neoplasias Esofágicas/patología , Regulación Neoplásica de la Expresión Génica , Humanos , Inmunohistoquímica , Pronóstico , Modelos de Riesgos Proporcionales , Transducción de Señal/fisiología , Proteína p53 Supresora de Tumor/metabolismo , Factor A de Crecimiento Endotelial Vascular/metabolismo
13.
Clin Infect Dis ; 33(9): e105-8, 2001 Nov 01.
Artículo en Inglés | MEDLINE | ID: mdl-11577375

RESUMEN

We describe a case of CMV ventriculoencephalitis in a severely immunocompromised bone marrow transplant recipient who was receiving combination therapy with ganciclovir and foscarnet for treatment of viremia and retinitis. Analysis of sequential viral isolates recovered from the patient's cerebrospinal fluid suggested that disease developed because of the presence of viral resistance and, possibly, low tissue penetration of antiviral agents.


Asunto(s)
Antivirales/uso terapéutico , Trasplante de Médula Ósea/efectos adversos , Retinitis por Citomegalovirus/virología , Citosina/análogos & derivados , Citosina/uso terapéutico , Farmacorresistencia Viral , Encefalitis Viral/virología , Foscarnet/uso terapéutico , Ganciclovir/uso terapéutico , Huésped Inmunocomprometido , Organofosfonatos , Compuestos Organofosforados/uso terapéutico , Ventrículos Cerebrales/virología , Niño , Cidofovir , Retinitis por Citomegalovirus/tratamiento farmacológico , Retinitis por Citomegalovirus/fisiopatología , Combinación de Medicamentos , Farmacorresistencia Viral/genética , Encefalitis Viral/tratamiento farmacológico , Encefalitis Viral/fisiopatología , Femenino , Humanos
15.
Mol Cell ; 4(5): 665-72, 1999 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-10619014

RESUMEN

In B. subtilis, the chromosome partitioning proteins Soj (ParA) and Spo0J (ParB) regulate the initiation of sporulation. Soj is a negative regulator of sporulation gene expression, and Spo0J antagonizes Soj function. Using fusions of Soj to green fluorescent protein, we found that Soj localized near the cell poles and upon entry into stationary phase oscillated from pole to pole. In the absence of Spo0J, Soj was associated predominantly with DNA. By in vivo cross-linking and immunoprecipitation, we found that Soj physically associates with developmentally regulated promoters, and this association increased in the absence of Spo0J. These results show that Soj switches localization and function depending on the chromosome partitioning protein Spo0J. We further show that mutations in the Soj ATPase domain disrupt localization and function and render Soj insensitive to regulation by Spo0J.


Asunto(s)
Bacillus subtilis/crecimiento & desarrollo , Bacillus subtilis/metabolismo , Proteínas Bacterianas/metabolismo , Factor sigma , Factores de Transcripción/metabolismo , Adenosina Trifosfatasas/antagonistas & inhibidores , Adenosina Trifosfatasas/química , Adenosina Trifosfatasas/genética , Adenosina Trifosfatasas/metabolismo , Adenosina Trifosfato/metabolismo , Bacillus subtilis/citología , Bacillus subtilis/genética , Proteínas Bacterianas/antagonistas & inhibidores , Proteínas Bacterianas/química , Proteínas Bacterianas/genética , Sitios de Unión , Polaridad Celular , Cromosomas Bacterianos/genética , Cromosomas Bacterianos/metabolismo , Secuencia Conservada , ADN Bacteriano/genética , ADN Bacteriano/metabolismo , Regulación Bacteriana de la Expresión Génica , Microscopía Fluorescente , Mutación/genética , Regiones Promotoras Genéticas/genética , Proteínas Recombinantes de Fusión/metabolismo , Esporas Bacterianas/citología , Esporas Bacterianas/genética , Esporas Bacterianas/crecimiento & desarrollo , Esporas Bacterianas/metabolismo , Factores de Transcripción/antagonistas & inhibidores , Factores de Transcripción/química , Factores de Transcripción/genética
16.
Cell ; 88(5): 667-74, 1997 Mar 07.
Artículo en Inglés | MEDLINE | ID: mdl-9054506

RESUMEN

To investigate chromosome segregation in B. subtilis, we introduced tandem copies of the lactose operon operator into the chromosome near the replication origin or terminus. We then visualized the position of the operator cassettes with green fluorescent protein fused to the Lac1 repressor. In sporulating bacteria, which undergo asymmetric cell division, origins localized near each pole of the cell whereas termini were restricted to the middle. In growing cells, which undergo binary fission, origins were observed at various positions but preferentially toward the poles early in the cell cycle. In contrast, termini showed little preference for the poles. These results indicate the existence of a mitotic-like apparatus that is responsible for moving the origin regions of newly formed chromosomes toward opposite ends of the cell.


Asunto(s)
Bacillus subtilis/genética , Cromosomas Bacterianos/fisiología , Origen de Réplica/genética , Esporas Bacterianas/fisiología , Bacillus subtilis/citología , Bacillus subtilis/crecimiento & desarrollo , División Celular/genética , Mutación/fisiología , Poliploidía
17.
J Cell Biol ; 128(6): 1095-109, 1995 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-7896874

RESUMEN

Tensin, an actin filament capping protein first purified from chicken gizzard, is localized to various types of adherens junctions in muscle and nonmuscle cells. In this paper, we describe the isolation and sequencing of tensin cDNA from a chicken cardiac library. The 6.3-kb chicken cardiac tensin cDNA encodes an open reading frame of 1,792 amino acids. Mammalian cells transfected with the chicken tensin cDNA expressed a polypeptide of approximately 200 kD recognizable by antibodies to chicken gizzard tensin. The expressed protein was incorporated into focal adhesions and other actin-containing structures in the transfected cells. To map the domain associated with tensin's high affinity, barbed-end F-actin-capping activity, bacterially expressed recombinant fusion proteins containing various segments of tensin were prepared and assayed for activity. The results of these experiments show that the high affinity capping domain (kD = 1.3 nM) lies within amino acid residues R1037-V1169. Additional studies on a shorter construct, S1061-H1145, showed that these 85 residues were sufficient for producing complete inhibition of actin polymerization and depolymerization. While this active domain is located within that of the "insertin" sequence (Weigt, C., A. Gaertner, A. Wegner, H. Korte, and H. E. Meyer. 1992. J. Mol. Biol. 227:593-595), our data showing complete inhibition of polymerization and shift in critical concentration are consistent with a simple barbed-end capping mechanism rather than the "insertin model." Our results also differ from those of a recent report (Lo, S. H., P. A. Janmey, J. H. Hartwig, and L. B. Chen. 1994. J. Cell Biol. 125:1067-1075), which concluded that their recombinant tensin has an "insertin-like" inhibitory effect on barbed-end actin polymerization, and that this activity is attributed to residues T936-R1037 (residues 888-989 in their numbering system). In our study, a fusion construct (N790-K1060) encompassing T936-R1037 had no significant effect on actin polymerization and depolymerization, even at high concentrations.


Asunto(s)
Proteínas de Microfilamentos/genética , Miocardio/química , Células 3T3 , Actinas/química , Secuencia de Aminoácidos , Animales , Secuencia de Bases , Línea Celular , Pollos , Clonación Molecular , Humanos , Ratones , Proteínas de Microfilamentos/biosíntesis , Proteínas de Microfilamentos/aislamiento & purificación , Datos de Secuencia Molecular , Unión Proteica , Secuencias Repetitivas de Ácidos Nucleicos , Homología de Secuencia , Tensinas
18.
Chin Med J (Engl) ; 105(5): 410-4, 1992 May.
Artículo en Inglés | MEDLINE | ID: mdl-1499373

RESUMEN

The five parameters including nuclear area (NA), nuclear perimeter (NP), nuclear diameter (ND), axis ratio and nuclear roundness were evaluated with MIAS200 Image Analysis System (Sichuan University, Chengdu) in 45 patients with laryngeal primary squamous cell carcinoma, which were confirmed pathologically and operated on from January 1977 to October 1987. The results showed that NA, NP and ND are important prognostic indicators. The survival rate in patients with large nuclei (NA greater than 73 microns2, NP greater than 32.5 microns, ND greater than 12 microns) was significantly lower than that in those with small nuclei (NA less than 73 microns2, NP less than 32.5 microns, ND less than 12 microns) (P less than 0.0025). These findings strongly suggest that patients with laryngeal squamous cell carcinoma with large nuclei should be treated more aggressively.


Asunto(s)
Carcinoma de Células Escamosas/ultraestructura , Núcleo Celular/ultraestructura , Neoplasias Laríngeas/ultraestructura , Adulto , Anciano , Femenino , Humanos , Procesamiento de Imagen Asistido por Computador , Masculino , Persona de Mediana Edad , Pronóstico
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