RESUMEN
Hemgn (a gene symbol for hemogen in mouse, EDAG in human and RP59 in rat) encodes a nuclear protein that is highly expressed in hematopoietic tissues and acute leukemia. To characterize its regulatory mechanisms, we examined the activities of a Hemgn promoter containing 2975 bp of 5' flanking sequence and 196 bp of 5' untranslated region (5' UTR) sequence both in vitro and in vivo: this promoter is preferentially activated in a hematopoietic cell line, not in nonhematopoietic cell lines, and is sufficient to drive the transcription of a lacZ transgene in hematopoietic tissues in transgenic mice. Mutagenesis analyses showed that the 5' UTR including two highly conserved GATA boxes is critical for the promoter activity. GATA1, not GATA2, binds to the GATA binding sites and transactivates the Hemgn promoter in a dose-dependent manner. Furthermore, the expression of human hemogen (EDAG) transcripts were closely correlated with levels of GATA1 transcripts in primary acute myeloid leukemia specimens. This study suggests that the Hemgn promoter contains critical regulatory elements for its transcription in hematopoietic tissues and Hemgn is a direct target of GATA1 in leukemia cells.
Asunto(s)
Células de la Médula Ósea/metabolismo , Factor de Transcripción GATA1/fisiología , Regulación Leucémica de la Expresión Génica , Leucemia Mieloide Aguda/genética , Proteínas Nucleares/genética , Regiones Promotoras Genéticas , Transcripción Genética , Regiones no Traducidas 5' , Animales , Secuencia de Bases , Línea Celular Tumoral , Niño , ADN , Humanos , Leucemia Mieloide Aguda/patología , Ratones , Ratones Transgénicos , Datos de Secuencia Molecular , Reacción en Cadena de la Polimerasa de Transcriptasa InversaRESUMEN
In this article, polyphosphate-accumulating organisms (PAOs) from a lab-scale continuous-flow two-sludge system was isolated and identified, the different phosphorus accumulation characteristics of the isolates under anoxic and aerobic conditions were investigated. Two kinds of PAOs were both found in the anoxic zones of the two-sludge system, one of them utilized only oxygen as electron acceptor, and the other one utilized either nitrate or oxygen as electron acceptor. Of the total eight isolates, five isolates were capable of utilizing both nitrate and oxygen as electron acceptors to uptake phosphorus to some extent. And three of the five isolates showed good phosphorus accumulative capacities both under anoxic or aerobic conditions, two identified as Alcaligenes and one identified as Pseudomonas. Streptococcus was observed weak anoxic phosphorus accumulation because of its weak denitrification capacity, but it showed good phosphorus accumulation capacity under aerobic conditions. One isolates identified as Enterobacteriaceae was proved to be a special species of PAOs, which could only uptake small amounts of phosphorus under anoxic conditions, although its denitrification capacity and aerobic phosphorus accumulation capacity were excellent.
Asunto(s)
Bacterias/metabolismo , Reactores Biológicos , Fósforo/metabolismo , Aerobiosis , Anaerobiosis , Bacterias/aislamiento & purificación , Recuento de Colonia Microbiana , Nitratos/metabolismo , Oxígeno/metabolismoRESUMEN
We cloned a novel murine gene, designated Hemogen (hemopoietic gene), which was sequentially expressed in active hematopoietic sites and downregulated in the process of blood cell differentiation. Hemogen transcripts were specifically detected in blood islands, primitive blood cells and fetal liver during embryogenesis, and then remained in bone marrow and spleen in adult mice. Immunostaining demonstrated that Hemogen was a nuclear protein. We also identified a human homologue of Hemogen, named EDAG, which was mapped to chromosome 9q22, a leukemia breakpoint. Like Hemogen, EDAG exhibited specific expression in hematopoietic tissues and cells. Taken together, these data are consistent with Hemogen and EDAG playing an important role in hematopoietic development and neoplasms.