Bruce Beutler

University of Texas Southwestern Medical Center | UT Southwestern · Center for the Genetics of Host Defense

In a genetic screen, we identified two viable missense alleles of the essential gene Midnolin (Midn) that were associated with reductions in peripheral B cells. Causation was confirmed in mice with targeted deletion of four of six MIDN protein isoforms. MIDN was expressed predominantly in lymphocytes where it augmented proteasome activity. We showe...

In mice, adenovirus (Ad)-elicited IFN-ab mediates the overproduction of LPS stimulated cytokines such as TNFa and IL-6. We found that Ad infection also mediates the overproduction of IFN-ab itself and enables its production in splenic marginal zone macrophages, which don’t produce IFN-ab in response to LPS alone. We show the importance of the scave...

Activated microglia have been implicated in the pathogenesis of age-related macular degeneration (AMD), diabetic retinopathy, and other neurodegenerative and neuroinfammatory disorders, but our understanding of the mechanisms behind their activation is in infant stages. With the goal of identifying novel genes associated with microglial activation...

We used N -ethyl- N -nitrosurea–induced germline mutagenesis combined with automated meiotic mapping to identify specific systolic blood pressure (SBP) and heart rate (HR) determinant loci. We analyzed 43,627 third-generation (G3) mice from 841 pedigrees to assess the effects of 45,378 variant alleles within 15,760 genes, in both heterozygous and h...

Phosphatidylinositol 3-kinase α, a heterodimer of catalytic p110α and one of five regulatory subunits, mediates insulin- and insulin like growth factor-signaling and, frequently, oncogenesis. Cellular levels of the regulatory p85α subunit are tightly controlled by regulated proteasomal degradation. In adipose tissue and growth plates, failure of K4...

Evolution depends upon genetic variations that influence physiology. As defined in a genetic screen, phenotypic performance may be enhanced or degraded by such mutations. We set out to detect mutations that influence motor function, including motor learning. Thus, we tested the motor effects of 36,444 non‐synonymous coding/splicing mutations induce...

Signals emanating from the T cell receptor (TCR), co-stimulatory receptors, and cytokine receptors each influence CD8 T cell fate. Understanding how these signals respond to homeostatic and microenvironmental cues can reveal new ways to therapeutically direct T cell function. Through forward genetic screening in mice, we discovered that loss-of-fun...

We detected ENU-induced alleles of Mfsd1 (encoding the major facilitator superfamily domain containing 1 protein) that caused lymphopenia, splenomegaly, progressive liver pathology, and extramedullary hematopoiesis (EMH). MFSD1 is a lysosomal membrane-bound solute carrier protein with no previously described function in immunity. By proteomic analy...

Distinct pathways and molecules may support embryonic versus postnatal thymic epithelial cell (TEC) development and maintenance. Here, we identify a mechanism by which TEC numbers and function are maintained postnatally. A viable missense allele (C120Y) of Ovol2, expressed ubiquitously or specifically in TECs, results in lymphopenia, in which T cel...

In a forward genetic screen of mice with N -ethyl- N -nitrosourea-induced mutations for aberrant immune function, we identified animals with low percentages of B220 ⁺ cells in the peripheral blood. The causative mutation was in Ier3ip1 , encoding immediate early response 3 interacting protein 1 (IER3IP1), an endoplasmic reticulum membrane protein m...

Intestinal immunity is dependent on barrier function to maintain quiescence. The mechanisms for the maintenance of this barrier are not fully understood. Delta 4-desaturase, sphingolipid 2 (DEGS2) is a lipid desaturase and hydroxylase, which catalyzes the synthesis of ceramide and phytoceramide from dihydroceramide. Using a forward genetic approach...

A key feature in intestinal immunity is the dynamic intestinal barrier, which separates the host from resident and pathogenic microbiota through a mucus gel impregnated with antimicrobial peptides. Using a forward genetic screen, we have found a mutation in Tvp23b, which conferred susceptibility to chemically induced and infectious colitis. Trans-G...

Rationale Essential functions of IgE have been attributed to specific glycosylations such as oligomannose (Fcer1a binding) and sialylation (pathogenicity). However, no study has examined how glycosylation affects IgE stability in vivo. Methods Forward genetic screening for IgE specific phenotypes was performed using N-ethyl-N-nitrosourea (ENU) mut...

Mice lacking the atypical inhibitory kappa B (IκB) protein, IκBNS, a regulator of the NF-κB pathway encoded by the nfkbid gene, display impaired antibody responses to both T cell-independent (TI) and T cell-dependent (TD) antigens. To better understand the basis of these defects, we crossed mice carrying floxed nfkbid alleles with mice expressing C...

Resting blood pressure (BP) and heart rate (HR) levels are independent risk factors for cardiovascular diseases and mortality. Both phenotypes are critical for lifetime maintenance of the cardiovascular homeostasis and are under the influence of multiple factors. The estimated heritability for both phenotypes is high, but their main genetic determi...

Obesity and diabetes are well known risk factors for nonalcoholic fatty liver disease (NAFLD), but the genetic factors contributing to the development of NAFLD remain poorly understood. Here we describe two semi-dominant allelic missense mutations (Oily and Carboniferous) of Predicted gene 4951 (Gm4951) identified from a forward genetic screen in m...

The diprovocims, a new class of toll-like receptor (TLR) agonists, bear no similarity to prior TLR agonists, act through a well-defined mechanism (TLR1/TLR2 agonist), exhibit exquisite structure-activity relationships, and display in vivo adjuvant activity. They possess potent and efficacious agonist activity toward human TLR1/TLR2 but modest agoni...

Significance Messenger RNA (mRNA) splicing is fundamental to protein expression in mammals. Homozygous deletion of single protein components of the splicing machinery or its regulatory factors is embryonic lethal. However, through forward genetic screening in mice, we identified a viable hypomorphic missense mutation of the splicing regulator RNPS1...

Genetic association studies of type 1 diabetes (T1D) in humans, and in congenic non-obese diabetic (NOD) mice harboring DNA segments from T1D-resistant mice, face the challenge of assigning causation to specific gene variants among many within loci that affect disease risk. Here, we created random germline mutations in NOD/NckH mice and used automa...

Significance A large body of evidence has indicated that recognition of self-nucleic acids by endosomal toll-like receptors (TLRs) is central to the pathogenesis of lupus-like systemic autoimmunity in spontaneous mouse models, and the solute carrier SLC15A4 is required for this recognition. Here we describe a mechanism in which SLC15A4 is a major c...

Significance The vast majority of autoimmune diseases are polygenic, and causal loci uncovered by genetic-mapping studies explain only a minority of the heritable contribution to trait variation. Multiple explanations for this missing heritability include rare meaningful variants, rare copy number variations or deletions, epistasis, epigenetics, di...

Significance Toll-like receptor 4 (TLR4) is an innate immune receptor that initiates inflammation when activated by bacterial lipopolysaccharide. It may also be activated by endogenous host molecules, leading to autoinflammation and autoimmunity. We demonstrate that several sulfatide species, natural membrane glycolipids in mammals, are bona fide l...

Significance We developed software called Candidate Explorer (CE) that uses a machine-learning algorithm to identify chemically induced mutations that are causative of screened phenotypes. CE determines the probability that a mutation will be verified as causative for a phenotype if the gene is independently targeted for knockout or recreation of t...

Precursor messenger RNA (pre-mRNA) splicing is catalyzed by an intricate ribonucleoprotein complex called the spliceosome. Although the spliceosome is considered to be general cell “housekeeping” machinery, mutations in core components of the spliceosome frequently correlate with cell- or tissue-specific phenotypes and diseases. In this review, we...

Embryonic formation and patterning of the vertebrate spinal column requires coordination of many molecular cues. After birth, the integrity of the spine is impacted by developmental abnormalities of the skeletal, muscular, and nervous systems, which may result in deformities such as kyphosis and scoliosis. We sought to identify novel genetic mouse...

A T cell sleeper agent against stress Considerable changes in cellular metabolism occur when T cells transition from a resting to an activated state. One side effect of this process is an increase in reactive oxygen species (ROS). These molecules potentiate T cell receptor (TCR) signaling but can also result in detrimental oxidative stress (see the...

Proper embryonic and post‐natal skeletal development require coordination of a myriad of complex molecular mechanisms. Disruption of these processes, through genetic mutation, contributes to variation in skeletal development. We developed a high‐throughput ENU‐induced saturation mutagenesis skeletal screening approach in mice to identify genes requ...

Many immune responses depend upon activation of NF-κB, an important transcription factor in the elicitation of a cytokine response. Here we show that N4BP1 inhibits TLR-dependent activation of NF-κB by interacting with the NF-κB signaling essential modulator (NEMO, also known as IκB kinase γ) to attenuate NEMO–NEMO dimerization or oligomerization....

Endoplasmic reticulum (ER) calcium (Ca2+ ) stores are critical to proteostasis, intracellular signaling, and cellular bioenergetics. Through forward genetic screening in mice, we identified two members of a new complex, Pacs1 and Wdr37, which are required for normal ER Ca2+ handling in lymphocytes. Deletion of Pacs1 or Wdr37 caused peripheral lymph...

Protein disulfide isomerase A6 (PDIA6) is an unfolded protein response (UPR)‐regulating protein. PDIA6 regulates the UPR sensing proteins, Inositol requiring enzyme 1, and EIF2AK3. Biallelic inactivation of the two genes in mice and humans resulted in embryonic lethality, diabetes, skeletal defects, and renal insufficiency. We recently showed that...

Here we report the isolation by selective breeding of two sublines of Non-Obese Diabetic (NOD) mice exhibiting a significant difference in the incidence of autoimmune type 1 diabetes (T1D). Whole genome sequencing of the NOD/Nck H (high T1D incidence) and NOD/Nck L (low T1D incidence) revealed the presence of a limited number of variants specific t...

Autism spectrum disorder (ASD) is a constellation of neurodevelopmental disorders with high phenotypic and genetic heterogeneity, complicating the discovery of causative genes. Through a forward genetics approach selecting for defective vocalization in mice, we identified Kdm5a as a candidate ASD gene. To validate our discovery, we generated a Kdm5...

When applied to immunity, forward genetic studies use meiotic mapping to provide strong statistical evidence that a particular mutation is causative of a particular immune phenotype. Notwithstanding this, co-segregation of multiple mutations, occasional unawareness of mutations, and paucity of homozygotes may lead to erroneous declarations of cause...

Many immune responses depend upon activation of NF-κB, a key transcription factor in the elicitation of a cytokine response. Here we demonstrate that N4BP1 inhibited TLR-dependent activation of NF-κB by interacting with the NF-κB signaling essential modulator (NEMO, also known as IκB kinase γ) to attenuate NEMO-NEMO dimerization or oligomerization....

Adenosine monophosphate deaminase 3 (Ampd3) encodes the erythrocyte isoform of the adenosine monophosphate (AMP) deaminase gene family. Mutations in this gene have been reported in humans, leading to autosomal-recessive erythrocyte AMP deaminase deficiency. However, the mutation is considered clinically asymptomatic. Using N-ethyl-N-nitrosourea mut...

Background Atopy, the overall tendency to become sensitized to an allergen, is heritable but seldom ascribed to mutations within specific genes. Atopic individuals develop abnormally elevated IgE responses to immunization with potential allergens. To gain insight into the genetic causes of atopy, we carried out a forward genetic screen for atopy in...

Retinal disease and loss of vision can result from any disruption of the complex pathways controlling retinal development and homeostasis. Forward genetics provides an excellent tool to find, in an unbiased manner, genes that are essential to these processes. Using N-ethyl-N-nitrosourea mutagenesis in mice in combination with a screening protocol u...

Significance To examine the function of KBTBD2 in different cell types, we knocked the gene out in adipocytes, liver, and muscle cells. None of these conditional knockouts could reproduce the growth retardation observed in mice with a global knockout. An adipose tissue-specific knockout was similar to a global knockout in most respects; however, hy...

The small GTPase RABL3 is an oncogene of unknown physiological function. Homozygous knockout alleles of mouse Rabl3 were embryonic lethal, but a viable hypomorphic allele (xiamen [xm]) causing in-frame deletion of four amino acids from the interswitch region resulted in profound defects in lymphopoiesis. Impaired lymphoid progenitor development led...

Significance Follicular B cells generally require T cell help to contribute to adaptive immunity, producing several isotypes of immunoglobulins that carry out distinct effector functions. Two specialized B cell subsets, marginal zone (MZ) and B-1 B cells, arise from different developmental steps and have different functions. They become activated t...

In a forward genetic screen of N-ethyl-N-nitrosourea (ENU)-induced mutant mice for aberrant immune function, we identified mice with a syndromic disorder marked by growth retardation, diabetes, premature death, and severe lymphoid and myeloid hypoplasia together with diminished T cell-independent (TI) antibody responses. The causative mutation was...

T follicular helper cells (T FH ) participate in germinal center (GC) development and are necessary for B cell production of high-affinity, isotype-switched antibodies. In a forward genetic screen, we identified a missense mutation in Prkd2 , encoding the serine/threonine kinase protein kinase D2, which caused elevated titers of immunoglobulin E (I...

The role of lipids in inflammasome activation remains underappreciated. The phospholipid, platelet-activating factor (PAF), exerts multiple physiological functions by binding to a G protein–coupled seven-transmembrane receptor (PAFR). PAF is associated with a number of inflammatory disorders, yet the molecular mechanism underlying its proinflammato...

We report a new immunodeficiency disorder in mice caused by a viable hypomorphic mutation of Snrnp40, an essential gene encoding a subunit of the U5 small nuclear ribonucleoprotein (snRNP) complex of the spliceosome. Snrnp40 is ubiquitous but strongly expressed in lymphoid tissue. Homozygous mutant mice showed hypersusceptibility to infection by mu...

The primary goals of modern genetics are to identify disease-causing mutations and to define the functions of genes in biological processes. Two complementary approaches, reverse and forward genetics, can be used to achieve this goal. Reverse genetics is a gene-driven approach that comprises specific gene targeting followed by phenotypic assessment...

Fibroblast growth factor 21 (FGF21) is an endocrine hormone that regulates glucose, lipid, and energy homeostasis. While gene expression of FGF21 is regulated by the nuclear hormone receptor peroxisome proliferator-activated receptor alpha in the fasted state, little is known about the regulation of trafficking and secretion of FGF21. We show that...

LPS-responsive beige-like anchor (LRBA) protein deficiency in humans causes immune dysregulation resulting in autoimmunity, inflammatory bowel disease (IBD), hypogammaglobulinemia, regulatory T (Treg) cell defects, and B cell functional defects, but the cellular and molecular mechanisms responsible are incompletely understood. In an ongoing forward...

Wnt signaling out on a limb The Wnt/β-catenin signaling pathway is central to hematopoietic stem cell (HSC) survival, renewal, and differentiation. Both excessive and insufficient β-catenin can have adverse consequences, so “destruction complexes” ensure its precise regulation. Using a mouse forward genetic screen, Choi et al. identified a mutation...

Diprovocim is a recently discovered exceptionally potent, synthetic small molecule agonist of TLR2/TLR1 and has shown significant adjuvant activity in anticancer vaccination against murine melanoma. Since Diprovocim bears no structural similarity to the canonical lipopeptide ligands of TLR2/TLR1, we investigated how Diprovocim interacts with TLR2/T...

Aryl hydrocarbon receptor nuclear translocator 2 (ARNT2) is a member of the basic helix-loop-helix/PER-ARNT-SIM (bHLH/PAS) transcription factor family. ARNT2 heterodimerizes with several members of the family, including single-minded homolog-1 (SIM1) and neuronal PAS domain protein 4 (NPAS4), primarily in neurons of the central nervous system. We s...

The SMCR8-WDR41-C9ORF72 complex is a regulator of autophagy and lysosomal function. Autoimmunity and inflammatory disease have been ascribed to loss-of-function mutations of Smcr8 or C9orf72 in mice. In humans, autoimmunity has been reported to precede amyotrophic lateral sclerosis caused by mutations of C9ORF72 However, the cellular and molecular...

A screen conducted with nearly 100,000 compounds and a surrogate functional assay for stimulation of an immune response that measured the release of TNF-alpha from treated human THP-1 myeloid cells differentiated along the macrophage line led to the discovery of the diprovocims. Unique to these efforts and of special interest, the screening leads f...

Myosin ID (MYO1D) is a member of the class I myosin family. We screened 48,649 third generation (G3) germline mutant mice derived from N-ethyl-N-nitrosourea-mutagenized grandsires for intestinal homeostasis abnormalities after oral administration of dextran sodium sulfate (DSS). We found and validated mutations in Myo1d as a cause of increased susc...

Significance Adjuvants enhance adaptive immune responses, sometimes through unknown mechanisms, and can be used to augment both humoral and cellular responses to cancer antigens. We report the immunological effects of the synthetic chemical adjuvant Diprovocim, which targets the innate immune receptor TLR1/TLR2 in mice and humans. Diprovocim displa...

B-1a cells are mainly generated from fetal liver progenitor cells, peri- and neonatally. The developmental steps and anatomical sites required for these cells to become mature B-1a cells remain elusive. We recently described a phenotypically distinct transitional B cell subset in the spleen of neonatal mice that generated B-1a cells when adoptively...

Bone marrow B-1a cell numbers are decreased in splenectomized mice. Adult 12-week-old wild-type mice were splenectomized or sham-operated and 10 days later stained for (A) peritoneal cavity and (B) bone marrow B-1a and B-2 cells (defined as in Figure 1). Graphs display mean ± SD. Statistically significant differences are indicated by *, denoting p...

Representative stainings of bone marrow B-lineage populations. (A) Staining of bone marrow pro-B, (B220+CD43+CD19+), pre-B (B220+CD43−CD93+IgM−), immature B (B220+CD43−CD93+IgM+), and mature B (B220+CD43−CD93−IgM+) cells (B) Staining of mature bone marrow B-1a (CD93−CD19hiB220loCD43+CD5+) and B-2 (CD93−CD19+B220+/−) cells. Representative plots are...

B-1a cell development from fetal liver cells transferred into already splenectomized hosts. Wild-type (wt) FL cells were isolated from 11 days old embryos (E11) and transferred to adult RAG1−/− mice that had undergone splenectomy or sham surgery 30 days earlier. At 6 weeks later the mice were sacrificed and analyzed for B-1a cells. Donor-derived B-...

Innate behaviors are genetically encoded, but their underlying molecular mechanisms remain largely unknown. Predator odor 2,4,5-trimethyl-3-thiazoline (TMT) and its potent analog 2-methyl-2-thiazoline (2MT) are believed to activate specific odorant receptors to elicit innate fear/defensive behaviors in naive mice. Here, we conduct a large-scale rec...

Although much is known about how mammals respond to allergens, it is still unclear how allergies are acquired. Allergies arise from environmental triggers, but the genetic causes are not clearly understood. We undertook a forward genetic approach to discover genes with non-redundant function in allergic sensitivity. Our screen measured antigen-spec...

Systemic lupus erythematosus (SLE) is an autoimmune disease caused by an immune response to many self-antigens, including DNA, histones, and RNA-binding proteins. One of the most physiologically relevant mouse models is the NZB/NZW F1 hybrid mouse, which develops SLE at high penetrance, in contrast to either parental strain. However, the critical g...

Although much is known about how mammals respond to allergens, it is still unclear how allergies are acquired. Allergies arise from environmental triggers, but the genetic causes are not clearly understood. We undertook a forward genetic approach to discover genes with non-redundant function in allergic sensitivity. Our screen measured antigen-spec...

The compensatory proliferation of insulin-producing β cells is critical to maintaining glucose homeostasis at the early stage of type 2 diabetes. Failure of β cells to proliferate results in hyperglycemia and insulin dependence in patients. To understand the effect of the interplay between β cell compensation and lipid metabolism upon obesity and p...

Computational inference of mutation effects is necessary for genetic studies in which many mutations must be considered as etiologic candidates. Programs such as PolyPhen-2 predict the relative severity of damage caused by missense mutations, but not the actual probability that a mutation will reduce/eliminate protein function. Based on genotype an...

Marginal zone (MZ) B cells reside in the splenic MZ and play important roles in T cell-independent humoral immune responses against blood-borne pathogens. IκBNS-deficient bumble mice exhibit a severe reduction in the MZ B compartment but regain an MZ B population with age and, thus, represent a valuable model to examine the biology of MZ B cells. I...

Type I IFN and nucleic acid-sensing TLRs are both strongly implicated in the pathogenesis of lupus, with most patients expressing IFN-induced genes in peripheral blood cells and with TLRs promoting type I IFNs and autoreactive B cells. About a third of systemic lupus erythematosus patients, however, lack the IFN signature, suggesting the possibilit...

Univariate and multivariate survival analysis in 185 CRC patients.

Antibodies and conjugates used for flow cytometry analysis.

Altered ratios of transcript isoforms in Triaka epithelial cells.

Gene expression and pathway analysis.

Correlation of hGPR137_Short with Wnt target genes.

Self-designed primers for qPCR analysis.

Association of (nuclear) ESRP1 expression with clinicopathological features in 185 CRC patients.

Transcriptional regulation of numerous interferon-regulated genes, including Toll-like receptor 3 ( Tlr3 ), which encodes an innate immune sensor of viral double-stranded RNA, depends on the interferon regulatory factor 1 (IRF1) and IRF2 transcription factors. We detected specific abrogation of macrophage responses to polyinosinic-polycytidylic aci...

ELife digest The lining of the intestine is just one cell thick, and yet it can act as an effective barrier between the inside of the body and the contents of the digestive system. This lining is often disturbed during bowel cancer, inflammatory bowel disease and other intestinal diseases, causing the barrier to fail and the gut to become leaky. Th...

GU-AG consensus sequences are used for intron recognition in the majority of cases of pre-mRNA splicing in eukaryotes. Mutations at splice junctions often cause exon skipping, short deletions, or insertions in the mature mRNA, underlying one common molecular mechanism of genetic diseases. Using N-ethyl-N-nitrosourea, a novel recessive mutation name...