Hands-on immunology: Engaging learners of all ages through tactile teaching tools.

Ensuring the public has a fundamental understanding of human-microbe interactions, immune responses, and vaccines is a critical challenge in the midst of a pandemic. These topics are commonly taught in undergraduate- and graduate-level microbiology and immunology courses; however, creating engaging methods of teaching these complex concepts to students of all ages is necessary to keep younger students interested when science seems hard. Building on the Tactile Teaching Tools with Guided Inquiry Learning (TTT-GIL) method we used to create an interactive operon molecular puzzle, we report here two TTT-GIL activities designed to engage diverse learners from middle schoolers to masters students in exploring molecular interactions within the immune system.

DNA double-strand breaks relieve USF-mediated repression of Dβ2 germline transcription in developing thymocytes.

Activation of germline promoters is central to V(D)J recombinational accessibility, driving chromatin remodeling, nucleosome repositioning, and transcriptional read-through of associated DNA. We have previously shown that of the two TCRβ locus (Tcrb) D segments, Dβ1 is flanked by an upstream promoter that directs its transcription and recombinational accessibility. In contrast, transcription within the DJβ2 segment cluster is initially restricted to the J segments and only redirected upstream of Dβ2 after D-to-J joining.

Genetic and epigenetic regulation of Tcrb gene assembly.

Vertebrate development requires the formation of multiple cell types from a single genetic blueprint, an extraordinary feat that is guided by the dynamic and finely tuned reprogramming of gene expression. The sophisticated orchestration of gene expression programs is driven primarily by changes in the patterns of covalent chromatin modifications. These epigenetic changes are directed by cis elements, positioned across the genome, which provide docking sites for transcription factors and associated chromatin modifiers.

Tetra-O-methyl nordihydroguaiaretic acid (Terameprocol) inhibits the NF-κB-dependent transcription of TNF-α and MCP-1/CCL2 genes by preventing RelA from binding its cognate sites on DNA.

Background: Tetra-O-methyl nordihydroguaiaretic acid, also known as terameprocol (TMP), is a naturally occurring phenolic compound found in the resin of the creosote bush. We have shown previously that TMP will suppress production of certain inflammatory cytokines, chemokines and lipids from macrophages following stimulation with LPS or infection with H1N1 influenza virus. In this study our goal was to elucidate the mechanism underlying TMP-mediated suppression of cytokine and chemokine production.

Fur negatively regulates hns and is required for the expression of HilA and virulence in Salmonella enterica serovar Typhimurium.

Iron is an essential element for the survival of living cells. However, excess iron is toxic, and its uptake is exquisitely regulated by the ferric uptake regulator, Fur. In Salmonella, the Salmonella pathogenicity island 1 (SPI-1) encodes a type three secretion system, which is required for invasion of host epithelial cells in the small intestine.

The center of accessibility: Dβ control of V(D)J recombination.

Developmental patterning of antigen receptor gene assembly in lymphocyte precursors correlates with decondensation of the chromatin surrounding individual gene segments. Ongoing V(D)J recombination is associated with hyperacetylation of histones H3 and H4 and the expression of sterile germline transcripts across the region of recombinational accessibility. Likewise, histone acetyltransferase and SWI/SNF chromatin remodeling complexes each appear to be required for recombination, and the PHD-finger of RAG-2 preferentially associates with recombination signal sequence (RSS) chromatin that contains H3 trimethylated on lysine 4.

Molybdenum and tungsten in Campylobacter jejuni: their physiological role and identification of separate transporters regulated by a single ModE-like protein.

Campylobacter jejuni is an important human pathogen that causes millions of cases of food-borne enteritis each year. The C. jejuni respiratory chain is highly branched and contains at least four enzymes predicted to contain a metal binding pterin (MPT), with the metal being either molybdenum or tungsten.

Promoter activity 5' of Dbeta2 is coordinated by E47, Runx1, and GATA-3.

V(D)J recombination involves the stepwise assembly of B and T cell receptor genes as lymphocytes progress through the early stages of development. While the mechanisms that restrict each step in recombination to its appropriate developmental stage are largely unknown, they share many of the components that regulate transcription. For example, enhancer-dependent modifications in histone acetylation and methylation are essential for both germline transcription and rearrangement of antigen receptor genes.

A streamlined method for rapid and sensitive chromatin immunoprecipitation.

We report a streamlined procedure to efficiently carry samples from chromatin to qPCR-compatible DNA in as little as 4 h. We use this streamlined ChIP to quantify histone H3 modifications at active (cad) and repressed (T early alpha) promoters in a Rag1-deficient pro-T cell line after 1-2 h IP. We further show that the protocol readily quantified histone modifications in chromatin from 10(4) Rag-deficient DN thymocytes.

Differential activation of dual promoters alters Dbeta2 germline transcription during thymocyte development.

Ag receptor genes are assembled through somatic rearrangements of V, D, and J gene segments. This process is directed in part by transcriptional enhancers and promoters positioned within each gene locus. Whereas enhancers coordinate reorganization of large chromatin stretches, promoters are predicted to facilitate the accessibility of proximal downstream gene segments.

Cancer predisposition and hematopoietic failure in Rad50(S/S) mice.

Mre11, Rad50, and Nbs1 function in a protein complex that is central to the metabolism of chromosome breaks. Null mutants of each are inviable. We demonstrate here that hypomorphic Rad50 mutant mice (Rad50(S/S) mice) exhibited growth defects and cancer predisposition.

Regulation of V(D)J recombination: a dominant role for promoter positioning in gene segment accessibility.

Antigen receptor gene assembly is regulated by transcriptional promoters and enhancers, which control the accessibility of gene segments to a lymphocyte-specific V(D)J recombinase. However, it remained unclear whether accessibility depends on the process of transcription itself or chromatin modifications that accompany transcription. By using T cell receptor beta substrates that integrate stably into nuclear chromatin, we show that promoter location, rather than germ-line transcription or histone acetylation, is a primary determinant of recombination efficiency.