David  G.  Schatz, PhD

Professor of Immunobiology; Professor of Molecular Biophysics and Biochemistry

Departments & Organizations

Immunobiology: Lymphocyte Development |Biological and Biomedical Sciences (BBS):Immunology; Molecular Cell Biology, Genetics and Development | Comprehensive Cancer Center:Immunology and Immunotherapy | Internal Medicine:Diabetes Endocrinology Research Center

Biographical Info

Dr. Schatz has made fundamental contributions to our understanding of the mechanisms that assemble and diversify antigen receptor genes that encode antibodies and T cell receptors.  He is best known for the discovery of RAG1 and RAG2, subsequent biochemical insights into RAG function and evolutionary origins, and the discovery of two distinct levels of regulation of somatic hypermutation.   

As a graduate student with David Baltimore, Schatz established an assay for the detection of V(D)J recombination activity and, in collaboration with Marjorie Oettinger, used this assay to isolate the Recombination Activating Genes RAG1 and RAG2, whose gene products constitute the vital, lymphocyte-specific components of the V(D)J recombination machinery.  This discovery transformed the field of V(D)J recombination and stands as a seminal event in the field of Immunology.  Schatz has since provided important insights into the mechanism of V(D)J recombination.  Schatz and Martin Gellert co-discovered the ability of RAG1/2 to perform DNA transposition, with implications for our understanding of the evolution of the adaptive immune system and the mechanism of V(D)J recombination.  Schatz has made important contributions to the field of somatic hypermutation, including the discovery of strand asymmetric spreading of mutations and the existence of two distinct levels of targeting of the reaction, one of which relies on gene-specific DNA repair:  error-prone at immunoglobulin genes and high-fidelity at numerous proto-oncogenes.  His laboratory remains interested in understanding the mechanism of regulation of V(D)J recombination and somatic hypermutation.   

Schatz has co-authored over 110 articles, many in prestigious journals, and has been the recipient of numerous prizes and awards, including the Rhodes Scholarship, the Snow Prize (Yale University's top award to a graduating senior), the National Science Foundation Presidential Faculty Fellows Award, and the American Association of Immunologists-BD Biosciences Investigator Award.  He has been active as an editor and reviewer, serving as Co-Editor of the journal Immunity, as a member of the editorial board of a number of journals, and as a member and Chair of the NIH study section Cellular and Molecular Immunology-A.  Schatz has also been very interested in graduate education, serving for many years as the Director of Graduate Studies and Graduate Admissions for Immunobiology and as a member of the Executive Committee of the Biological and Biomedical Sciences (BBS) Program.   

Schatz received B.S. and M.S. degrees in Molecular Biophysics and Biochemistry from Yale University in 1980, and a M.A. degree in Philosophy and Politics from Oxford University in 1982.  His Ph.D. degree (1990) and postdoctoral training were done with Dr. David Baltimore at the Massachusetts Institute of Technology and the Whitehead Institute for Biomedical Research.

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Education & Training

Ph.D.

Massachusetts Institute of Technology (1990)

Postdoctoral Fellow

Whitehead Institute and MIT, Department of Biology (1990 - 1991)

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Honors & Recognition

• Snow Prize, Yale University's top overall award to a graduating student
  Yale University (1980)
• Rhodes Scholarship
  (1980)
• Cheryl Whitlock/Pathology Prize for the outstanding contribution to the fields of hematopoiesis and leukemogenesis by an individual during training.
  (1991)
• National Science Foundation Presidential Faculty Fellows Award
  National Science Foundation (1994)
• AAI-BD Biosciences Investigator Award
  American Association of Immunology (2004)
• MERIT Award, NIAID, NIH
  National Institutes of Health (2007)

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Professional Service

• Chair, NIH Study Section CMI-A (2008 - 2010)
• Regular member, NIH Study Section CMI-A (2004 - 2006)
• Editorial Board, Immunological Reviews (2003 - 2008)
• Editorial Board, Immunity (2003)
• Co-Editor, Immunity (2000 - 2003)
• Editorial Board, Molecular and Cellular Biology (1996)

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Research Interests

Biochemical mechanism and developmental regulation of V(D)J recombination and somatic hypermutation; lymphocyte development; mechanisms of DNA repair; function of the RAG1 and RAG2 proteins; mechanisms of lymphomagenesis

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Research Summary

Generating a Diverse and Effective Repertoire of Antibodies During an Immune Response   

The Schatz laboratory studies V(D)J recombination and somatic hypermutation, reactions that create and optimize antibody genes.  Antibodies are blood proteins produced by B cells that are important for fighting infectious disease. V(D)J recombination puts antibody genes together from small pieces of chromosomal DNA, while somatic hypermutation makes mutations in antibody genes and allows for the generation of antibodies that bind viruses and bacteria very tightly.  We study these reactions using a wide variety of molecular, genetic, cellular, and biochemical approaches.  The focus of our research is understanding the underlying mechanisms of these reactions and how they are targeted specifically to antibody genes.  We are also very interested in understanding why V(D)J recombination and somatic hypermutation sometimes affect the wrong genes, and how such mistakes contribute to the development of B cell cancers known as lymphomas and leukemias.

Extensive Research Description

Generating a Diverse and Effective Repertoire of Antigen-Specific Receptors During Development of the Immune System

The B and T lymphocytes that constitute the adaptive immune system make use of antigen receptor molecules, known as immunoglobulins and T cell receptors, to combat viral and bacterial infections. Each of the hundreds of millions of lymphocytes expresses a different antigen receptor on its surface, indicative of an extraordinary level of diversity in these receptors. The fundamental interest of our lab is to understand the two major processes that generate this diversity: V(D)J recombination and somatic hypermutation.

V(D)J recombination assembles immunoglobulin and T cell receptor genes from component V (variable), D (diversity), and J (joining) gene segments in developing B and T cells. In the first phase of the reaction, two DNA segments are bound by the recombination machinery, brought into close physical proximity, and the DNA is cleaved. In the second phase, the DNA ends are processed and joined by the cellular DNA repair machinery to form the reaction products.

One of our major interests is the enzymatic mechanism of the first phase of V(D)J recombination, which is catalyzed by the proteins encoded by the recombination-activating genes, RAG1 and RAG2. We are studying how the RAG proteins bend and twist the substrate DNA during DNA cleavage and have developed fluorescence resonance energy transfer (FRET) as a method to study the structure of protein-DNA complexes formed by the RAG proteins. We are using a variety of ensemble and single molecule biophysical assays to characterize the structure, composition, and stability of the DNA complexes formed by RAG1/RAG2.

Recently, we have used chromatin immunoprecipitation (ChIP) to determine the pattern of binding of RAG1 and RAG2 to antigen receptor loci in developing lymphocytes. We find that the RAG proteins associate with one small, discrete region of each antigen receptor locus. These regions, which we refer to as recombination centers, are rich in activating histone modifications and RNA polymerase II. We propose that recombination centers are specialized sites within which the RAG proteins bind one DNA segment and then capture a second to allow for recombination. Interestingly, each RAG protein has the ability to be recruited into recombination centers in the absence of the other, suggesting several distinct levels of regulation of RAG binding. We are currently using ChIP combined with parallel sequencing (ChIP-seq) to determine the pattern of binding of RAG1 and RAG2 through the genome in developing B and T lymphocytes. We hope that this study will shed light on the rules that dictate normal and aberrant binding of the RAG proteins and on how the RAG proteins contribute to genome instability and cancer.

Somatic hypermutation introduces point mutations into the variable regions of immunoglobulin genes (which encode antibodies) in B cells during an immune response. These mutations allow for the generation of B cells expressing antibodies with high affinity for an invading microorganism, a process known as affinity maturation. This process is important for the "memory" of the immune system, which helps protect individuals from recurrent infections with the same microorganism, and underlies the success of many vaccines.

Somatic hypermutation is initiated by an enzyme known as activation-induced deaminase (AID), which deaminates cytosine to create uracil in immunoglobulin genes. The uracil is then processed by the mismatch and base excision repair pathways to create mutations at the site of deamination and at nearby sites in the DNA. Somatic hypermutation has been linked to genomic instability and B cell cancers, and our lab is interested in understanding how the reaction is targeted to immunoglobulin loci and how the rest of the genome is protected from its deleterious effects. We have demonstrated that the immunoglobulin promoter plays a significant role in determining the efficiency of somatic hypermutation, and we are investigating the role of promoters and other DNA elements in immunoglobulin loci in the targeting of the reaction. A major focus of our work is to identify the DNA sequences that recruit AID preferentially to immunoglobulin genes.

We have discovered that the genome is protected from damage due to somatic hypermutation by two distinct mechanisms: specific targeting of AID and gene-specific, high-fidelity DNA repair. AID preferentially deaminates immunoglobulin genes, and our data demonstrate that many genes avoid the action of AID altogether. Surprisingly, however, a large number of non-immunoglobulin genes are hit by AID but fail to accumulate mutations because the uracils are repaired in a high-fidelity manner. These genes include many, such as Myc, that have been implicated in the development of B cell malignancies. It is clear that AID acts more widely in the genome than previously suspected. An important implication of these findings is that anything that undermines high-fidelity DNA repair would be expected to allow for widespread accumulation of mutations, with potentially disastrous consequences. We are testing the hypothesis that cellular stress, viral infection, or the early steps in malignant transformation perturb high-fidelity repair and thereby contribute to or hasten the development of cancer.

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Selected Publications

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幾乎所有 review paper 都出自他的手

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