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Research Interests - Dr. Michael J. Pikaart

Protein-DNA Interactions in the Developing Red Blood Cell and Interference by Toxic Metals

The Pikaart lab studies the molecular basis for the specific binding of Gata-1, a hematopoietic transcription factor, to DNA. Gata-1 is required for the maturation of bone marrow stem cells into functional circulating blood cells. Gata-1 functions in the regulation of cell growth, allowing for continuing cell division during hematopoietic differentiation, as well as activating transcription of blood cell-specific proteins, such as hemoglobin. Interplay between the several Gata protein family members and with other transcription factor, both general and tissue-specific, is complex and involves subtle distinctions among various regulatory outcomes depending on context. Thus, a more thorough understanding of the means by which Gata recognizes regulatory binding sites in DNA provides a revealing look at the mechanisms by which DNA-binding proteins find their DNA targets during the course of gene regulation.

We are examing the role of five amino acid side chains in direct contact with the DNA major groove when Gata binds DNA. Several mutations to these structurally central amino acids have been found which preserve DNA binding in Gata's minimal DNA binding domain. Because these represent mutants not found in naturally-occuring Gata-1, current plans are to introduce these changes back into full-length Gata. Additionally, we have discovered a strongly inhibitory effect of the toxic heavy metal lead on Gata DNA binding and function. Since lead is known to exert pathological effects on the hematopoietic system, a goal of our work is to test whether Gata is a molecular target for lead toxicity in cell culture systems.