Key Points Novel GM-CSF signaling pathways through IFN-γR/IRF-1 and AKT/mTOR provide monocyte licensing for suppressor function. Only licensed but not fresh Ly-6Chigh murine or human CD14+ monocytes secrete nitric oxide or IDO for T-cell suppression.
We have isolated and characterized a fragment of the gene encoding adipose fatty acid-binding protein (gene 422) from a 3T3-L1 adipocyte genomic library. The 5'-flanking sequence of the 422 gene contains potential regulatory regions for adipose-specific expression. At position -120 there is a fat-specific element that occurs in several genes expressed as preadipocytes differentiate, and at position -393 there is a glucocorticoid regulatory element core sequence. Chimeric constructs were prepared by ligating 858 base pairs or 248 base pairs of 5'-flanking sequence and 22 nucleotides of 5'-untranslated sequence of the 422 gene to the bacterial gene encoding chloramphenicol acetyltransferase (CAT); these constructs (A858.CAT and A248.CAT) were transfected into 3T3-L1 preadipocytes. When differentiation was initiated by the adipogenic agents methylisobutylxanthine (a cAMP phosphodiesterase inhibitor), dexamethasone, and insulin, expression of both constructs increased, reaching maximal levels within 24 hr. Both constructs were maximally induced 48 hr before appreciable accumulation of the endogenous 422 mRNA. Expression of A858.CAT, but not of A248.CAT, was induced by dexamethasone, which correlates with deletion of the potential glucocorticoid regulatory element. Expression of both constructs was induced by 8-bromoadenosine 3',5'-cycic monophosphate, thus implicating the first 248 base pairs of 5'-flanking sequence of the 422 gene in the response to cAMP. Indirect effects by the adipogenic factors on CAT protein or mRNA synthesis and turnover were ruled out, since replacing the 5'-flanking region of the 422 gene constructs with viral promoters abolished the effects of dexamethasone and 8-bromoadenosine 3',5'-cyclic monophosphate on CAT expression. We conclude that the first 858 base pairs of 5'-flanking sequence of the 422 gene contains elements that mediate activation by dexamethasone and cAMP.Green and Kehinde (1, 2) have established several 3T3 cell lines that differentiate into adipocytes in response to appropriate stimuli. The expression of adipocyte morphology by these cells is accompanied by the specific reprogramming of enzymatic and regulatory functions to those typical of adipose cells. The accumulation of cytoplasmic triglyceride that occurs during differentiation is correlated with a coordinate rise in the activity of every enzyme of the pathways of de novo fatty acid and triglyceride synthesis (3-7). In addition, 3T3 preadipocytes acquire the enzymatic capacity to mobilize triglyceride (8) and respond with great sensitivity to lipogenic (9-11) and lipolytic hormones (12). There is now compelling evidence (13-15) that the increase in the levels of the specific translatable mRNAs for these differentiationinduced proteins is responsible for the observed increases in their expression during 3T3 preadipocyte differentiation, which in all cases thus far examined depends on increased transcription of the corresponding genes (16-18).We (19) Cell Culture. 3T3-L1 preadipocytes were maintained and induce...
The C-module-binding factor (CbfA) is a multidomain protein that belongs to the family of jumonji-type (JmjC) transcription regulators. In the social amoeba Dictyostelium discoideum, CbfA regulates gene expression during the unicellular growth phase and multicellular development. CbfA and a related D. discoideum CbfA-like protein, CbfB, share a paralogous domain arrangement that includes the JmjC domain, presumably a chromatin-remodeling activity, and two zinc finger-like (ZF) motifs. On the other hand, the CbfA and CbfB proteins have completely different carboxy-terminal domains, suggesting that the plasticity of such domains may have contributed to the adaptation of the CbfA-like transcription factors to the rapid genome evolution in the dictyostelid clade. To support this hypothesis we performed DNA microarray and real-time RT-PCR measurements and found that CbfA regulates at least 160 genes during the vegetative growth of D. discoideum cells. Functional annotation of these genes revealed that CbfA predominantly controls the expression of gene products involved in housekeeping functions, such as carbohydrate, purine nucleoside/nucleotide, and amino acid metabolism. The CbfA protein displays two different mechanisms of gene regulation. The expression of one set of CbfA-dependent genes requires at least the JmjC/ZF domain of the CbfA protein and thus may depend on chromatin modulation. Regulation of the larger group of genes, however, does not depend on the entire CbfA protein and requires only the carboxy-terminal domain of CbfA (CbfA-CTD). An AT-hook motif located in CbfA-CTD, which is known to mediate DNA binding to A+T-rich sequences in vitro, contributed to CbfA-CTD-dependent gene regulatory functions in vivo.
Performance of ETFE membrane cushion constructions Roof or facade constructions made of pneumatically supported membrane cushions show a very dynamic and complex behavior under changing environmental conditions. For proper design of these constructions, the construction material, and the details of manufacture must be understood completely. Therefore, this article addresses some special requirements for the construction material ethylene tetrafluoroethylene (ETFE) and their consequences for using behavior. At first, the design and manufacture relevant details of membrane cushion constructions are described. The state of the design and interpretation of these structures is summarized and problems, based on the special characteristics of this material, are noted. The property profile of the structural material is discussed in relation to the occurring load conditions, and the requirements for material tests are discussed. Investigations which are carried out at Fraunhofer Institute for Mechanics of Materials and their relation to the modeling of the materials behavior are explained. Finally, a shot outlook describes the next steps to clarify the material model
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