A repressor is a protein that turns off the expression of one or more genes. The repressor protein works by binding to the gene's promoter region, preventing the production of messenger RNA (mRNA).
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A repressor is a protein that has a negative effect on gene expression. So these usually are proteins that bind to DNA, and they either prevent the RNA transcription machinery from getting in there and transcribing that DNA, or they just slow it down. So repressors are present in cells where you don't want a particular gene expressed. So if the repressor cell recognizes a sequence in that gene, it will travel to there and keep that gene off in that cell. And this is how you prevent hemoglobin from being expressed in neurons, and how you would prevent liver enzymes from being expressed in red blood cells. Repressors are very difficult to study because it's much easier to study things that give you more of what you're looking for. But I think as we go along we're going to find they play as important a role in gene regulation as the activating proteins.
David M. Bodine, Ph.D.
Chief and Senior Investigator, Genetics and Molecular Biology Branch; Head, Hematopoiesis Section
Dr. Bodine's laboratory investigates the genetics of pluripotent hematopoietic stem cells (PHSCs) to improve the effectiveness of bone marrow transplantation and find better ways to use these unique cells for gene replacement therapy. PHSCs are found mainly in bone marrow. These cells proliferate and differentiate into all the cell types of the peripheral blood. PHSCs also can self-renew without differentiating. A major limitation to bone marrow transplantation is the lack of availability of stem cells. His laboratory seeks to understand and control the self-renewal of PHSCs in order to amplify them, thereby improving stem cell transplantation and gene therapy techniques.