R01AI187357

Contributions of BRWD1-mediated cohesin conversion to B cell biology - Project summary

In developing B cells, and in the germinal center (GC), genomic mechanisms of diversity must be strictly coordinated with those of proliferative selection.

Failure to do so risks genomic instability and leukemic transformation.

In the bone marrow (BM), this is done by ordering B lymphopoiesis into alternating and mutually exclusive states of either stochastic immunoglobulin gene (IG) recombination or cell proliferation with selection.

Likewise, GC B cells are divided into three subpopulations that occupy different niches and compartmentalize the incompatible functions of proliferation, somatic hypermutation and selection.

In both the BM and GC, transit between proliferation and DNA mutation states requires large reordering of both genomic accessibility and transcription.

In the BM, the epigenetic reader BRWD1 orchestrates the radical change in enhancer landscapes when cells exit proliferation and initiate IGK recombination.

We have recently demonstrated that it does this by converting static to dynamic cohesin at topologically associating domain (TAD) boundaries.

Dynamic cohesin then extrudes DNA across TADs to appose promoters and enhancers for gene activation and to contract IGK for recombination.

We now provide preliminary evidence suggesting that BRWD1 is recruited to these TAD boundaries by specialized CTCF sites flanked by DNA GAGA sequences and that GAGA motifs are important for both BRWD1 recruitment and function.

Finally, we demonstrate that deleting BRWD1 in GCs leads to disordered subsets and diminished function.

Overall, our findings support a model in which BRWD1 orchestrates essential B cell functions, in both the BM and GC, by regulating dynamic cohesin-mediated chromatin topology to both determine enhancer landscapes and poise immunoglobulin genes for recombination.

Specific aims:

Aim 1. To define BRWD1 GC functions and determine if these are associated with cohesin conversion.

Hypothesis: We hypothesize that BRWD1 and cohesin conversion are used, and reused, to rewire B cell gene topology across cell state transitions.

Aim 2: Determine the mechanisms and functional importance of BRWD1-mediated GAGA motif recognition.

Hypothesis: BRWD1 recognizes GAGA motifs and this is important for both BRWD1 chromatin binding and chromatin remodeling.

Aim 3. Determine how the recruitment of BRWD1 and cohesin are coordinated for cohesin conversion.

Hypothesis: CTCF assembles BRWD1 with cohesin at TAD boundaries to orchestrate cohesin conversion.

University Of Chicago

TO ASSIST PUBLIC AND PRIVATE NONPROFIT INSTITUTIONS AND INDIVIDUALS TO ESTABLISH, EXPAND AND IMPROVE BIOMEDICAL RESEARCH AND RESEARCH TRAINING IN INFECTIOUS DISEASES AND RELATED AREAS, TO CONDUCT DEVELOPMENTAL RESEARCH, TO PRODUCE AND TEST RESEARCH MATERIALS. TO ASSIST PUBLIC, PRIVATE AND COMMERCIAL INSTITUTIONS TO CONDUCT DEVELOPMENTAL RESEARCH, TO PRODUCE AND TEST RESEARCH MATERIALS, TO PROVIDE RESEARCH SERVICES AS REQUIRED BY THE AGENCY FOR PROGRAMS IN INFECTIOUS DISEASES, AND CONTROLLING DISEASE CAUSED BY INFECTIOUS OR PARASITIC AGENTS, ALLERGIC AND IMMUNOLOGIC DISEASES AND RELATED AREAS. PROJECTS RANGE FROM STUDIES OF MICROBIAL PHYSIOLOGY AND ANTIGENIC STRUCTURE TO COLLABORATIVE TRIALS OF EXPERIMENTAL DRUGS AND VACCINES, MECHANISMS OF RESISTANCE TO ANTIBIOTICS AS WELL AS RESEARCH DEALING WITH EPIDEMIOLOGICAL OBSERVATIONS IN HOSPITALIZED PATIENTS OR COMMUNITY POPULATIONS AND PROGRESS IN ALLERGIC AND IMMUNOLOGIC DISEASES. BECAUSE OF THIS DUAL FOCUS, THE PROGRAM ENCOMPASSES BOTH BASIC RESEARCH AND CLINICAL RESEARCH. SMALL BUSINESS INNOVATION RESEARCH (SBIR) PROGRAM EXPANDS AND IMPROVES PRIVATE SECTOR PARTICIPATION IN BIOMEDICAL RESEARCH. THE SBIR PROGRAM INTENDS TO INCREASE AND FACILITATE PRIVATE SECTOR COMMERCIALIZATION OF INNOVATIONS DERIVED FROM FEDERAL RESEARCH AND DEVELOPMENT, TO INCREASE SMALL BUSINESS PARTICIPATION IN FEDERAL RESEARCH AND DEVELOPMENT, AND TO FOSTER AND ENCOURAGE PARTICIPATION OF SOCIALLY AND ECONOMICALLY DISADVANTAGED SMALL BUSINESS CONCERNS AND WOMEN-OWNED SMALL BUSINESS CONCERNS IN TECHNOLOGICAL INNOVATION. THE SMALL BUSINESS TECHNOLOGY TRANSFER (STTR) PROGRAM STIMULATES AND FOSTERS SCIENTIFIC AND TECHNOLOGICAL INNOVATION THROUGH COOPERATIVE RESEARCH AND DEVELOPMENT CARRIED OUT BETWEEN SMALL BUSINESS CONCERNS AND RESEARCH INSTITUTIONS, TO FOSTER TECHNOLOGY TRANSFER BETWEEN SMALL BUSINESS CONCERNS AND RESEARCH INSTITUTIONS, TO INCREASE PRIVATE SECTOR COMMERCIALIZATION OF INNOVATIONS DERIVED FROM FEDERAL RESEARCH AND DEVELOPMENT, AND TO FOSTER AND ENCOURAGE PARTICIPATION OF SOCIALLY AND ECONOMICALLY DISADVANTAGED SMALL BUSINESS CONCERNS AND WOMEN-OWNED SMALL BUSINESS CONCERNS IN TECHNOLOGICAL INNOVATION. RESEARCH CAREER DEVELOPMENT AWARDS SUPPORT THE DEVELOPMENT OF SCIENTISTS DURING THE FORMATIVE STAGES OF THEIR CAREERS. INDIVIDUAL NATIONAL RESEARCH SERVICE AWARDS (NRSAS) ARE MADE DIRECTLY TO APPROVE APPLICANTS FOR RESEARCH TRAINING IN SPECIFIED BIOMEDICAL SHORTAGE AREAS. IN ADDITION, INSTITUTIONAL NATIONAL RESEARCH SERVICE AWARDS ARE MADE TO ENABLE INSTITUTIONS TO SELECT AND MAKE AWARDS TO INDIVIDUALS TO RECEIVE TRAINING UNDER THE AEGIS OF THEIR INSTITUTIONAL PROGRAM.

93.855 - Allergy and Infectious Diseases Research

National Institute of Allergy and Infectious Diseases (NIAID) [HHS - NIH]

Illinois United States

State-Wide

NIH Research Project Grant (Parent R01 Clinical Trial Not Allowed) (PA-20-185)