Studies on Human γ-globin Gene Regulation: Transcription Factors in a Rubik’s Cube

The red blood cell is one of the most important blood cells in the human body. Hemoglobin is the major protein in the red blood cell, and functions as a gas transporter (oxygen and carbon dioxide) to all parts of the body. Changes in the structure or the amount of hemoglobin (hemoglobinopathy) affect the function of red blood cells with consequences for human health. An example are sickle cell anemia and thalassemia. During human development, in the fetus there is mainly fetal hemoglobin and in just after birth it is replaced by adult hemoglobin. The mechanism of this process is not completely understood. In order to gain more insight in the globin gene regulation process, I generated a human globin locus reporter mouse model in which the fetal and adult globin genes are modified by introducing two fluorescent proteins. Fetal liver cell lines were established from these transgenic mice and were used as an erythroid in vitro model to study responses to genetic manipulation, such as modulating the expression of potential regulators of fetal globin gene expression by shRNA mediated knockdown. In addition, I constructed a lentivirus-based naïve library of llama antibodies (HCAbs) that I transduced into the reporter transgenic mouse cell lines, trying to identify potential antibodies that could reactivate the fetal globin gene. I also characterized basal transcription factors of the TFIID complex in erythroid cells and found stoichiometric differences of some TFIID members during erythroid differentiation and distinct SAGA complexes, which I linked to fetal globin expression.

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