RESUMO
Signaling through the IL-7 receptor (IL-7R) is required for development and maintenance of the immune system. The receptor for IL-7 is heterodimeric, consisting of a common gamma chain (gammac, encoded by Il2rg) and an alpha subunit (IL-7Ralpha, encoded by Il7r). The Il7r gene is expressed specifically in the immune system in a developmental stage-specific manner. It is not known how the Il7r gene is transcriptionally regulated during B cell development. The goal of this study is to elucidate the function of the Il7r promoter region in developing B cells. Using a combination of 5' rapid amplification of cDNA ends analysis, transient transfection assays, and DNase I hypersensitivity mapping, we identified the location of the Il7r promoter. Using a combination of electrophoretic mobility shift analysis, chromatin immunoprecipitation experiments, and RNA interference experiments, we found that the Ets transcription factors PU.1 and GA-binding protein (GABP) activate the Il7r promoter by interacting with a highly conserved Ets binding site. In committed B lineage cells, GABP can promote Il7r transcription in the absence of PU.1. However, the results of retroviral gene transfer experiments suggest that PU.1 is uniquely required to initiate transcription of the Il7r locus at the earliest stages of progenitor B cell generation. In summary, these results suggest that Il7r transcription is regulated by both PU.1 and GABP in developing B cells.
Assuntos
Linfócitos B/metabolismo , Fator de Transcrição de Proteínas de Ligação GA/metabolismo , Regiões Promotoras Genéticas , Proteínas Proto-Oncogênicas/metabolismo , Receptores de Interleucina-7/metabolismo , Transativadores/metabolismo , Sequência de Bases , Núcleo Celular/metabolismo , Imunoprecipitação da Cromatina , Pegada de DNA , Ensaio de Desvio de Mobilidade Eletroforética , Citometria de Fluxo , Humanos , Dados de Sequência Molecular , Reação em Cadeia da Polimerase , Receptores de Interleucina-7/genética , Retroviridae/genética , Homologia de Sequência do Ácido Nucleico , Linfócitos T/metabolismo , Transcrição Gênica , Ativação Transcricional , TransfecçãoRESUMO
Density functional theory and infrared spectroscopy were used to determine the structure of N,O-dilithio-2-(N-methylamino)ethanol, a mixed intramolecular aggregate. The calculations indicated that the cyclic form of this compound is more stable than the open form, and that conclusion is consistent with the infrared spectra. The solid-state spectra showed lower Li-N and Li-O vibrational frequencies than were calculated for the gas phase, which is consistent with coordination of lithium to electronegative atoms on adjacent molecules in the solid state.
