Microbiology Commons^™

Genomic Vs. Non-Genomic Role Of The Ahr In Human Immunoglobulin Expression, Nasser Alhamdan

Browse all Theses and Dissertations

The immunoglobulin heavy chain gene (Igh) in various animal models is regulated by numerous regulatory elements including the 3’Igh regulatory region (3’IghRR). Several transcription factors are involved in modulating the 3’IghRR including the aryl hydrocarbon receptor (AhR). The AhR is a ligand-activated transcription factor that mediates the transcription of genes involved in the metabolism of environmental toxicants such as TCDD. TCDD binds AhR and regulates immunoglobulin (Ig) expression in B cells. This modulation appears to be directly mediated by binding of the AhR to dioxin response elements (DRE) within the 3’IghRR. In human B cells, IgG secretion inhibited by TCDD …

Genomic Vs. Non-Genomic Role Of The Ahr In Human Immunoglobulin Expression, Nasser Alhamdan

Browse all Theses and Dissertations

The immunoglobulin heavy chain gene (Igh) in various animal models is regulated by numerous regulatory elements including the 3'Igh regulatory region (3'IghRR). Several transcription factors are involved in modulating the 3'R including the aryl hydrocarbon receptor (AhR). The AhR is a ligand-activated transcription factor that mediates the transcription of genes involved in the metabolism of environmental toxicants such as TCDD. TCDD binds AhR and regulates immunoglobulin (Ig) expression in B cells. This modulation appears to be directly mediated by binding of the AhR to dioxin response elements (DRE) within the 3'IghRR. In human B cells, IgG secretion inhibited by TCDD …

Determining The Role Of The Ahr In Immunoglobulin Expression And Class Switch Recombination, Bassam Fawaz Kashgari

Browse all Theses and Dissertations

The aryl hydrocarbon receptor (AhR) is a ligand-activated cytosolic transcription factor that regulates xenobiotic-metabolizing enzymes. It mediates the toxicity of various environmental chemicals such as 2,3,7,8-tetracholorodibenzo-p-dioxin (TCDD). TCDD inhibits the differentiation of B cells into antibody-secreting cells and inhibits immunoglobulin (Ig) expression in various animal models. We have previously determined that TCDD-induced inhibition of the mouse Ig heavy chain gene (mo-Igh) is AhR-dependent. This inhibition may be mediated by binding of the AhR to dioxin response elements (DREs) within the 3'Igh regulatory region (3'IghRR) and inhibition of 3'IghRR activity, a significant transcriptional regulator of Ig expression. However, there are structural …

Elucidating The Effects Of Tcdd On The Polymorphic Human Hs1,2 Enhancer, Abdullah Freiwan

Browse all Theses and Dissertations

2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) is a potent environmental toxin known to inhibit immunoglobulin (Ig) gene expression in various animal studies. We have identified the mouse 3'Ig heavy chain regulatory region (3'IgH RR) as a sensitive transcriptional target of TCDD, which may mediate the inhibitory effect of TCDD on Ig expression. Interestingly, the human hs1,2 enhancer is polymorphic and has been associated with a number of autoimmune diseases.

Suggesting a species difference, TCDD inhibited mouse hs1,2 enhancer activation and activated basal human hs1,2 (hs-hs1,2) enhancer activity in the mouse B-cell line. The objective of this study was to elucidate the effects of TCDD …

The Im-9 Cell Line: A Model For Evaluating Tcdd-Induced Modulation Of The Polymorphic Human Hs1,2 Enhancer Within The 3' Immunoglobulin Heavy Chain Regulatory Region, Ruth C. Chambers-Turner

Browse all Theses and Dissertations

2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), a disrupter, of B-cell differentiation, induces binding of the aryl hydrocarbon receptor (AhR) nuclear complex to dioxin responsive elements (DRE) within the mouse immunoglobulin heavy chain regulatory region (3'IgHRR), and produces a marked inhibition of 3'IgHRR activation, IgH expression, and antibody secretion in a well-characterized mouse B-cell line (CH12.LX). The mouse 3'IgHRR consists of at least four enhancers (hs3a; hs1,2; hs3b; hs4), and is highly homologous with the three enhancers (hs3; hs1,2; hs4) of the human 3'IgHRR. A polymorphism of the human hs1,2 enhancer (resulting in varying numbers of tandem repeats containing a DRE and κB site) has …