A series of
gusA transcriptional fusion vectors is described for
Bacillus subtilis (Bs). The series includes a vector for use with the
amyE system of Shimotsu and Henner Gene 43 (1986) 85-94-1, an ...integrative vector and vectors that provide
gusA or
gusA neo cassettes. The
gusA fusions are compatible with
lacZ fusion vectors that are widely used with
Bs, and
gusA and
lacZ fusions are expressed at similar levels. β-Glucuronidase (βGlu) and β-galactosidase (βGal) do not exhibit any cross-reactivity, there is very little endogenous βGlu activity in
Bs, and there is no indication of mutation to high-level expression. We have used strains containing both
gusA and
lacZ fusions to compare the times of expression of different genes during sporulation.
Although IL-12 and IL-23 share the common p40 subunit, IL-23, rather than IL-12, seems to drive the pathogenesis of experimental autoimmune encephalomyelitis and arthritis, because IL-23/p19 knockout ...mice are protected from disease. In contrast, we describe in this study that newly created LacZ knockin mice deficient for IL-23 p19 were highly susceptible for the development of experimental T cell-mediated TNBS colitis and showed even more severe colitis than wild-type mice by endoscopic and histologic criteria. Subsequent studies revealed that dendritic cells from p19-deficient mice produce elevated levels of IL-12, and that IL-23 down-regulates IL-12 expression upon TLR ligation. Finally, in vivo blockade of IL-12 p40 in IL-23-deficient mice rescued mice from lethal colitis. Taken together, our data identify cross-regulation of IL-12 expression by IL-23 as novel key regulatory pathway during initiation of T cell dependent colitis.
Background Resistin-like molecule (RELM) β is a cysteine-rich cytokine expressed in the gastrointestinal tract and implicated in insulin resistance and gastrointestinal nematode immunity; however, ...its function primarily remains an enigma. Objective We sought to elucidate the function of RELM-β in the gastrointestinal tract. Methods We generated RELM-β gene-targeted mice and examined colonic epithelial barrier function, gene expression profiles, and susceptibility to acute colonic inflammation. Results We show that RELM-β is constitutively expressed in the colon by goblet cells and enterocytes and has a role in homeostasis, as assessed by alterations in colon mRNA transcripts and epithelial barrier function in the absence of RELM-β. Using acute colonic inflammatory models, we demonstrate that RELM-β has a central role in the regulation of susceptibility to colonic inflammation. Mechanistic studies identify that RELM-β regulates expression of type III regenerating gene (REG) (REG3β and γ), molecules known to influence nuclear factor κB signaling. Conclusions These data define a critical role for RELM-β in the maintenance of colonic barrier function and gastrointestinal innate immunity. Clinical implications These findings identify RELM-β as an important molecule in homeostatic gastrointestinal function and colonic inflammation, and as such, these results have implications for a variety of human inflammatory gastrointestinal conditions, including allergic gastroenteropathies.
Differentiation and recruitment of alternatively activated macrophages (AAMacs) are hallmarks of several inflammatory conditions associated with infection, allergy, diabetes, and cancer. AAMacs are ...defined by the expression of Arginase 1, chitinase-like molecules, and resistin-like molecule (RELM) alpha/FIZZ1; however, the influence of these molecules on the development, progression, or resolution of inflammatory diseases is unknown. We describe the generation of RELM-alpha-deficient (Retnla(-/-)) mice and use a model of T helper type 2 (Th2) cytokine-dependent lung inflammation to identify an immunoregulatory role for RELM-alpha. After challenge with Schistosoma mansoni (Sm) eggs, Retnla(-/-) mice developed exacerbated lung inflammation compared with their wild-type counterparts, characterized by excessive pulmonary vascularization, increased size of egg-induced granulomas, and elevated fibrosis. Associated with increased disease severity, Sm egg-challenged Retnla(-/-) mice exhibited elevated expression of pathogen-specific CD4(+) T cell-derived Th2 cytokines. Consistent with immunoregulatory properties, recombinant RELM-alpha could bind to macrophages and effector CD4(+) Th2 cells and inhibited Th2 cytokine production in a Bruton's tyrosine kinase-dependent manner. Additionally, Retnla(-/-) AAMacs promoted exaggerated antigen-specific Th2 cell differentiation. Collectively, these data identify a previously unrecognized role for AAMac-derived RELM-alpha in limiting the pathogenesis of Th2 cytokine-mediated pulmonary inflammation, in part through the regulation of CD4(+) T cell responses.
Sporulation of Bacillus subtilis requires the coordinated expression of two separate developmental programs in the mother cell and forespore compartments by σEand σF, respectively. This coordination ...is maintained through the action of cross-regulatory factors that control the activities of the various sporulation-specific σ factors. We present here the isolation and characterization of one such cross-regulatory factor, the spoIIR gene. Using a genetic screen, we have isolated four mutant alleles of spoIIR. These mutants were isolated as expressing σF-directed genes but not σE-directed genes. The block in σE-directed gene expression in spoIIR mutants was caused by an inability to process pro-σEto its active form. Cloning and characterization of the spoIIR gene determined that its transcription is directed by σF. Thus, SpoIIR is required for linking the activation of σEto the activation of σFand coordinating the initiation of the two developmental programs required to form a spore.
Sporulation of Bacillus subtilis requires the coordinated expression of two separate developmental programs in the mother cell and forespore compartments by sigmaE and sigmaF, respectively. A study ...isolated and characterized spoIIR, a gene that is required for the processing of pro-sigmaE and whose transcription is directed by sigmaF.
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