Louisiana Tech University

Postdoc

Jamie worked at Louisiana Tech University as a Postdoc

Louisiana Tech University

Associate Professor, School of Biological Sciences

Jamie worked at Louisiana Tech University as a Associate Professor, School of Biological Sciences

Louisiana Tech University

Associate Dean for Research and Graduate Studies, College of Applied and Natural Sciences

Jamie worked at Louisiana Tech University as a Associate Dean for Research and Graduate Studies, College of Applied and Natural Sciences

Louisiana Tech University

Visiting Assistant Professor of Biomedical Engineering

Jamie worked at Louisiana Tech University as a Visiting Assistant Professor of Biomedical Engineering

Louisiana Tech University

Assistant Professor, School of Biological Sciences

Jamie worked at Louisiana Tech University as a Assistant Professor, School of Biological Sciences

Centenary College of Louisiana

Visiting Lecturer

Bioethics taught in collaboration with Dr. Chris Ciocchetti

LSUHSC

Postdoc

Studied the role of SIRT1 in breast cancer.

Poly (ethylene glycol) hydrogel elasticity influences human mesenchymal stem cell behavior

Regenerative Biomaterials

Poly (ethylene glycol) hydrogel elasticity influences human mesenchymal stem cell behavior

Regenerative Biomaterials

Notch3 is involved in adipogenesis of human adipose-derived stromal/stem cells

Biochimie

Poly (ethylene glycol) hydrogel elasticity influences human mesenchymal stem cell behavior

Regenerative Biomaterials

Notch3 is involved in adipogenesis of human adipose-derived stromal/stem cells

Biochimie

Mediator and cohesin connect gene expression and chromatin architecture.

Nature

Transcription factors control cell-specific gene expression programs through interactions with diverse coactivators and the transcription apparatus. Gene activation may involve DNA loop formation between enhancer-bound transcription factors and the transcription apparatus at the core promoter, but this process is not well understood. Here we report that mediator and cohesin physically and functionally connect the enhancers and core promoters of active genes in murine embryonic stem cells. Mediator, a transcriptional coactivator, forms a complex with cohesin, which can form rings that connect two DNA segments. The cohesin-loading factor Nipbl is associated with mediator-cohesin complexes, providing a means to load cohesin at promoters. DNA looping is observed between the enhancers and promoters occupied by mediator and cohesin. Mediator and cohesin co-occupy different promoters in different cells, thus generating cell-type-specific DNA loops linked to the gene expression program of each cell.

Poly (ethylene glycol) hydrogel elasticity influences human mesenchymal stem cell behavior

Regenerative Biomaterials

Notch3 is involved in adipogenesis of human adipose-derived stromal/stem cells

Biochimie

Mediator and cohesin connect gene expression and chromatin architecture.

Nature

Transcription factors control cell-specific gene expression programs through interactions with diverse coactivators and the transcription apparatus. Gene activation may involve DNA loop formation between enhancer-bound transcription factors and the transcription apparatus at the core promoter, but this process is not well understood. Here we report that mediator and cohesin physically and functionally connect the enhancers and core promoters of active genes in murine embryonic stem cells. Mediator, a transcriptional coactivator, forms a complex with cohesin, which can form rings that connect two DNA segments. The cohesin-loading factor Nipbl is associated with mediator-cohesin complexes, providing a means to load cohesin at promoters. DNA looping is observed between the enhancers and promoters occupied by mediator and cohesin. Mediator and cohesin co-occupy different promoters in different cells, thus generating cell-type-specific DNA loops linked to the gene expression program of each cell.

Master transcription factors determine cell-type-specific responses to TGF-β signaling.

Cell

Transforming growth factor beta (TGF-β) signaling, mediated through the transcription factors Smad2 and Smad3 (Smad2/3), directs different responses in different cell types. Here we report that Smad3 co-occupies the genome with cell-type-specific master transcription factors. Thus, Smad3 occupies the genome with Oct4 in embryonic stem cells (ESCs), Myod1 in myotubes, and PU.1 in pro-B cells. We find that these master transcription factors are required for Smad3 occupancy and that TGF-β signaling largely affects the genes bound by the master transcription factors. Furthermore, we show that induction of Myod1 in nonmuscle cells is sufficient to redirect Smad3 to Myod1 sites. We conclude that cell-type-specific master transcription factors determine the genes bound by Smad2/3 and are thus responsible for orchestrating the cell-type-specific effects of TGF-β signaling.

Poly (ethylene glycol) hydrogel elasticity influences human mesenchymal stem cell behavior

Regenerative Biomaterials

Notch3 is involved in adipogenesis of human adipose-derived stromal/stem cells

Biochimie

Mediator and cohesin connect gene expression and chromatin architecture.

Nature

Transcription factors control cell-specific gene expression programs through interactions with diverse coactivators and the transcription apparatus. Gene activation may involve DNA loop formation between enhancer-bound transcription factors and the transcription apparatus at the core promoter, but this process is not well understood. Here we report that mediator and cohesin physically and functionally connect the enhancers and core promoters of active genes in murine embryonic stem cells. Mediator, a transcriptional coactivator, forms a complex with cohesin, which can form rings that connect two DNA segments. The cohesin-loading factor Nipbl is associated with mediator-cohesin complexes, providing a means to load cohesin at promoters. DNA looping is observed between the enhancers and promoters occupied by mediator and cohesin. Mediator and cohesin co-occupy different promoters in different cells, thus generating cell-type-specific DNA loops linked to the gene expression program of each cell.

Master transcription factors determine cell-type-specific responses to TGF-β signaling.

Cell

Transforming growth factor beta (TGF-β) signaling, mediated through the transcription factors Smad2 and Smad3 (Smad2/3), directs different responses in different cell types. Here we report that Smad3 co-occupies the genome with cell-type-specific master transcription factors. Thus, Smad3 occupies the genome with Oct4 in embryonic stem cells (ESCs), Myod1 in myotubes, and PU.1 in pro-B cells. We find that these master transcription factors are required for Smad3 occupancy and that TGF-β signaling largely affects the genes bound by the master transcription factors. Furthermore, we show that induction of Myod1 in nonmuscle cells is sufficient to redirect Smad3 to Myod1 sites. We conclude that cell-type-specific master transcription factors determine the genes bound by Smad2/3 and are thus responsible for orchestrating the cell-type-specific effects of TGF-β signaling.

Connecting transcriptional control to chromosome structure and human disease.

CSHL Symposium Quantitative Biology

We review key insights into transcriptional regulation of cell state that have emerged from the study of embryonic stem cells. These insights are described in the context of historical studies of the roles of transcription factors, signal transduction pathways, and regulators of chromatin structure. We highlight recent studies that have led to the model that mediator and cohesin physically and functionally connect the enhancers and core promoters of a key subset of active genes in cells, thus generating cell-type-specific DNA loops linked to the gene-expression program of each cell. Mutations in the genes encoding mediator and cohesin components can cause an array of human developmental syndromes and diseases, and we discuss the implications of these findings for the mechanisms involved in these diseases.

Poly (ethylene glycol) hydrogel elasticity influences human mesenchymal stem cell behavior

Regenerative Biomaterials

Notch3 is involved in adipogenesis of human adipose-derived stromal/stem cells

Biochimie

Mediator and cohesin connect gene expression and chromatin architecture.

Nature

Transcription factors control cell-specific gene expression programs through interactions with diverse coactivators and the transcription apparatus. Gene activation may involve DNA loop formation between enhancer-bound transcription factors and the transcription apparatus at the core promoter, but this process is not well understood. Here we report that mediator and cohesin physically and functionally connect the enhancers and core promoters of active genes in murine embryonic stem cells. Mediator, a transcriptional coactivator, forms a complex with cohesin, which can form rings that connect two DNA segments. The cohesin-loading factor Nipbl is associated with mediator-cohesin complexes, providing a means to load cohesin at promoters. DNA looping is observed between the enhancers and promoters occupied by mediator and cohesin. Mediator and cohesin co-occupy different promoters in different cells, thus generating cell-type-specific DNA loops linked to the gene expression program of each cell.

Master transcription factors determine cell-type-specific responses to TGF-β signaling.

Cell

Transforming growth factor beta (TGF-β) signaling, mediated through the transcription factors Smad2 and Smad3 (Smad2/3), directs different responses in different cell types. Here we report that Smad3 co-occupies the genome with cell-type-specific master transcription factors. Thus, Smad3 occupies the genome with Oct4 in embryonic stem cells (ESCs), Myod1 in myotubes, and PU.1 in pro-B cells. We find that these master transcription factors are required for Smad3 occupancy and that TGF-β signaling largely affects the genes bound by the master transcription factors. Furthermore, we show that induction of Myod1 in nonmuscle cells is sufficient to redirect Smad3 to Myod1 sites. We conclude that cell-type-specific master transcription factors determine the genes bound by Smad2/3 and are thus responsible for orchestrating the cell-type-specific effects of TGF-β signaling.

Connecting transcriptional control to chromosome structure and human disease.

CSHL Symposium Quantitative Biology

We review key insights into transcriptional regulation of cell state that have emerged from the study of embryonic stem cells. These insights are described in the context of historical studies of the roles of transcription factors, signal transduction pathways, and regulators of chromatin structure. We highlight recent studies that have led to the model that mediator and cohesin physically and functionally connect the enhancers and core promoters of a key subset of active genes in cells, thus generating cell-type-specific DNA loops linked to the gene-expression program of each cell. Mutations in the genes encoding mediator and cohesin components can cause an array of human developmental syndromes and diseases, and we discuss the implications of these findings for the mechanisms involved in these diseases.

Tcf3 is an integral component of the core regulatory circuitry of embryonic stem cells

Genes & Development

Embryonic stem (ES) cells have a unique regulatory circuitry, largely controlled by the transcription factors Oct4, Sox2, and Nanog, which generates a gene expression program necessary for pluripotency and self-renewal. How external signals connect to this regulatory circuitry to influence ES cell fate is not known. We report here that a terminal component of the canonical Wnt pathway in ES cells, the transcription factor T-cell factor-3 (Tcf3), co-occupies promoters throughout the genome in association with the pluripotency regulators Oct4 and Nanog. Thus, Tcf3 is an integral component of the core regulatory circuitry of ES cells, which includes an autoregulatory loop involving the pluripotency regulators. Both Tcf3 depletion and Wnt pathway activation cause increased expression of Oct4, Nanog, and other pluripotency factors and produce ES cells that are refractory to differentiation. Our results suggest that the Wnt pathway, through Tcf3, brings developmental signals directly to the core regulatory circuitry of ES cells to influence the balance between pluripotency and differentiation.