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C Gongora

Publications and source records attributed to C Gongora.

7 recordsLinked to original sources
PubMed2000

A unique ISRE, in the TATA-less human Isg20 promoter, confers IRF-1-mediated responsiveness to both interferon type I and type II.

Interferons (IFNs) encode a family of secreted proteins involved in a number of regulatory functions such as control of cell proliferation, differentiation and regulation of the immune system. Their diverse biological actions are thought to be mediated by the products of specific but usually overlapping sets of cellular genes induced in the target cells. We have recently isolated a human cDNA encoding a new nuclear bodies-associated protein (PML-NBs), which we have termed Isg20. In this report, we describe the cloning and functional characterization of the Isg20 promoter region and the identification of sequence elements and trans-acting factors implicated in its regulation. In the absence of any recognizable TATA or CAAT elements, Isg20 promoter basal activity is dependent upon the positive transcription factors Sp-1 and USF-1. Interestingly, we demonstrate that a unique interferon stimulated response element (ISRE) mediates both IFN type I and type II Isg20 induction in the absence of functional gamma-activated sequence. These inductions are strictly dependent upon of the IFN regulatory factor 1 (IRF-1). In addition, we show that the ISRE is also implicated in the constitutive transcriptional activity of Isg20 gene.

Base Sequence↗
PubMed2000

The interferon-inducible Staf50 gene is downregulated during T cell costimulation by CD2 and CD28.

It is well established that interferons (IFN) exert potent regulatory effects on the immune system. We have recently isolated a new IFN-induced human cDNA coding for a member of the Ring finger B-box/B30.2 subfamily that localizes to the chromosome band 11p15. We have named it Staf50. We show in this report that Staf50 is expressed in resting T cells in the absence of exogenous IFN treatment and is strongly repressed during T cell activation by anti-CD28 and anti-CD2 monoclonal antibodies (mAb) at both messenger and protein levels. In addition, we show that several members of the Ring finger B-box/B30.2 subfamily, including the 52-kDa SSA/Ro autoantigen, localize to the same chromosome band, 11p15, and are upregulated by IFN. These data led us to define a family of IFN-induced genes clustered on chromosome 11p15 that may be involved in T cell regulatory processes.

Amino Acid Sequence↗
PubMed1999

[Interferon signaling pathways].

Interferons (IFNs) encode a large family of multifonctional secreted proteins that are involved in antiviral defense, the regulation of cell growth and modulation of the immune response. They are subdivided into two types that activate transduction pathways via different cell surface receptors. Binding of both IFN type I and II results in the differential activation of JAK (Janus kinases) that phosphorylate latent cytoplasmic transcription factors termed STATs (signal transducer and activator of transcription). Phosphorylated STATs translocate to the nucleus, bind specific DNA elements and direct transcription. Type I IFN induces the phosphorylation of STAT1 and STAT2 proteins by tyrosine phosphorylation involving the type I IFN receptor-associated tyrosine kinases TYK2 and JAK1. Following phosphorylation, STAT1 and STAT2 form the transcriptionally active IFN-stimulated gene factor 3 (ISGF3) by association with a protein of the IFN regulatory factor (IRF) family, p48. The specificity of the transcriptional activation by ISGF3 is mediated by specific elements termed IFN-stimulatory response element (ISRE) located in the promoter region of IFN-inducible genes. ISREs drive the expression of most IFN type I-regulated genes and a few IFN type II-regulated genes. Gene induction by type II IFN involves the phosphorylation of only STAT1 by JAK1 and Jak2 kinases. This phosphorylation generates a homodimer of STAT1 which is able to bind the IFNgamma-activated site (GAS) to activate transcription. This signaling is rapid and direct. Molecules involved in the IFN signaling pathways have been shown to be used by other polypeptide ligands in their own signal transduction pathways. Pathways other than JAK/STAT are also involved in IFN signaling, but their mechanisms are less clear. The best documented are the mitogen-activated protein kinase (MAPK) cascade, the components of the TCR (T cell receptor) signaling cascade and the Pi3 kinase pathway.

Enzyme Activation↗
PubMed1997

Molecular cloning of a new interferon-induced PML nuclear body-associated protein.

Transcriptional induction of genes is an essential part of the cellular response to interferons. We have established a cDNA library from human lymphoblastoid Daudi cells treated for 16 h with human alpha/beta-interferon (IFN) and made use of differential screening to search for as yet unidentified IFN-regulated genes. In the course of this study, we have isolated a human cDNA that codes for a 20-kDa protein sharing striking homology with the product of the Xenopus laevis XPMC2 gene. This new gene is induced by both type I and II IFNs in various cell lines and will be referred to as ISG20 for interferon-stimulated gene product of 20 kDa. Confocal immunofluorescence analysis of the subcellular localization of ISG20 protein reveals that it is closely associated with PML and SP100 gene products within the large nuclear matrix-associated multiprotein complexes termed the PML nuclear bodies.

Amino Acid Sequence↗
PubMed1996

Quantitative analysis of the expression of the HLA-DRB genes at the transcriptional level by competitive polymerase chain reaction.

In addition to polymorphism of the peptide-binding site, the density of the MHC class II molecules expressed on the membrane of APC could well play a significant role in the MHC-peptide-TCR interaction during the immune response. We therefore investigated the regulation of the expression of the HLA-DRB genes at the transcriptional level. A competitive PCR approach was used to estimate the quantities of the HLA-DRB transcripts in peripheral blood B cells. When comparing the amounts of steady-state mRNAs among the different DRB1 alleles, the DRB1 transcripts in the DR52 haplotype group were found to be 2.5 to 3.5 times more abundant than the DRB1*01 transcripts, 1.5 to 2 times more abundant than the DRB1*04 transcripts, and 7 times more abundant than the DRB1*08 transcripts. Within the DR52 haplotype group, the DRB1 and DRB3 transcripts had the same abundance. Taken together, these results are in good agreement with the previously reported transcriptional activities of the DRB promoters except for DRB1*04, thus suggesting a differential post-transcriptional regulation among the DRB1 mRNAs.

Alleles↗
PubMed1988

Pharmacokinetics of plasmatic plasminogen activator in rabbits.

The pharmacokinetic characteristics of APP were studied in 10 male New Zealand rabbits. An initial dose of 15,000 IU of APP per kg of weight was administered. The respective fibrinolytic activity was estimated by fibrin plates and transformed according to theoretical considerations. Knorre's criterion was used for the determination of the number of compartments. In every case the values were below 0.2 which indicates a one-compartment open model. The data were fitted to the proposed model in two steps; first the stripping method was used, afterwards the values obtained by the stripping were used as initial values for nonlinear fitting by means of nonlin programs.

Absorption↗