FIGURE 1. Effects of cytokines on iNos and VCAM-I steady-state mRNA levels and t
ID: 186885 • Letter: F
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FIGURE 1. Effects of cytokines on iNos and VCAM-I steady-state mRNA levels and transcription HUVEC. Primary HUVEC were stimulated with vehicle (negative control), TNF-a (10 ng/ml), or a cytokine mixture (Cyt) of IFN-Y (200 U/ml), IL-18 (5 ng/ml), and TNF-a (10 ng/ml) for 4 h, after which RNA and chromatin extracts were isolated. A. Quantitative RT-PCR of human iNOS and VCAM-1 mRNA. Inducible NOS and VCAM-1 mRNA expressions were normalized to GAPDH mRNA level (in arbitrary units). Data represent the mean + SEM of four independent experiments. B, ChIP assay using an antibody directed against RNA polymerase II (Pol II). IP DNA was analyzed by quantitative PCR using iNOS and VCAMI promoter-specific primers. Data represent the meant SD of triplicate measurements from one of four independent experiments with similar results. *pExplanation / Answer
I have 2 reasonings for explain this:
1.- With the information provided by the graph we observed that the iNOS gene is activated by vehicle (I guess it's a negative control), as well as TNF-, When we see the mixture of cytokines we observed that TNF- is included. Why do I do observation on this?
It may sound technical, but it is important to distinguish the molecules either by their function or their origin, because in a certain way it is wrong to put all the molecules interchangeably as cytokines (for immunology, cytokine it is used to refer to all the molecules of intercellular communication, in spite of this, many lymphokines and monokynes are still described on the basis of their biological effect as in the case of tumor necrosis factors alpha and beta [TNF-, TNF-] among others.) Based on the fact that the tumor necrosis factor is not necessarily a cytokine, it could have activated the gene.
2.- Another reasoning that I can give you: if in "vehicle" that is the negative control there is activity, it means that this gene is constitutive (that is, independently of the conditions it will always be expressed) and that is why is unresponsive to cytokines
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