Category Archives: Useful Image/Diagrams

Kaposi’s sarcoma-associated herpesvirus vIRFs bind to cellular proteins, block transcription, and interfere with interferon and cellular signaling pathways

fimmu-02-00019-g001Viral infection activates cellular IRFs, including IRF1, 3, 5, and 7 to initiate IFN transcription. Binding of cellular IRFs by vIRF1 or vIRF3 results in a blockade of IFNα, β, and γ transcription. vIRF1 inhibits type I IFN transcription by binding the CBP/p300 transcriptional coactivator and inhibiting its activity. Viral infection also induces NF-κB transcription that is decreased by vIRF3. vIRF1, 3, and 4 inhibit p53 transcription and impede p53-mediated cell death. Other cell death processes affected by vIRFs include vIRF1 binding to GRIM19, vIRF3 interaction with 14-3-3 and FOXO3a, vIRF1 and 2 blockade of CD95L production, and vIRF1-mediated nuclear localization of Bim. In addition to deregulating immune responses and cell death, vIRFs have other roles such as vIRF3 increasing Myc and HIF-1α transcription and blocking expression of MHC II. vIRF1 blocks TGF-β signaling through binding to Smad3 and Smad4 and vIRF4 binding to the Notch transcription factor, CSL/CBF1 to inhibit activation of Notch target genes.

 

Reference:

Front. Immunol., 17 June 2011 | doi: 10.3389/fimmu.2011.00019

Random gene expression model

Aire contributes to random activation of genes by loosening up the chromatin structure to increase the general accessibility of TRA genes. This would in turn allow the recruitment of transcriptional activators to bind genes that would otherwise be physically restrictedfimmu-02-00014-g002

 

Reference:

Front. Immunol., 09 May 2011 | doi: 10.3389/fimmu.2011.00014

Diagrammatic representation of aspiration of bronchus content

aspiration of bronchus contentFigure 3. Diagrammatic representation of aspiration of bronchus content (including bacteria) into gut (1) to stimulate Peyer’s patches (3) to release T-lymphocytes which “home” to the bronchus (4) where they – directly or indirectly – secrete cytokines and chemokines which augment recruitment and activation of phagocytes (5) which reduce colonizing load of damaged bronchus mucosa. Ingestion of inactivated non-typeable Haemophilus influenzae (2) augments this protective “loop”.

 

Reference:

Front. Immunol., 15 March 2011 | doi: 10.3389/fimmu.2011.00007